Artykuły w czasopismach na temat „RUNT domain family”
Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: RUNT domain family.
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych artykułów w czasopismach naukowych na temat „RUNT domain family”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj artykuły w czasopismach z różnych dziedzin i twórz odpowiednie bibliografie.
1
Thirunavukkarasu, Kannan, Muktar Mahajan, Keith W. McLarren, Stefano Stifani i Gerard Karsenty. "Two Domains Unique to Osteoblast-Specific Transcription Factor Osf2/Cbfa1 Contribute to Its Transactivation Function and Its Inability To Heterodimerize with Cbfβ". Molecular and Cellular Biology 18, nr 7 (1.07.1998): 4197–208. http://dx.doi.org/10.1128/mcb.18.7.4197.
Pełny tekst źródłaStreszczenie:
ABSTRACT Osf2/Cbfa1, hereafter called Osf2, is a member of the Runt-related family of transcription factors that plays a critical role during osteoblast differentiation. Like all Runt-related proteins, it contains a runt domain, which is the DNA-binding domain, and a C-terminal proline-serine-threonine-rich (PST) domain thought to be the transcription activation domain. Additionally, Osf2 has two amino-terminal domains distinct from any other Runt-related protein. To understand the mechanisms of osteoblast gene regulation by Osf2, we performed an extensive structure-function analysis. After defining a short Myc-related nuclear localization signal, a deletion analysis revealed the existence of three transcription activation domains and one repression domain. AD1 (for activation domain 1) comprises the first 19 amino acids of the molecule, which form the first domain unique to Osf2, AD2 is formed by the glutamine-alanine (QA) domain, the second domain unique to Osf2, and AD3 is located in the N-terminal half of the PST domain and also contains sequences unique to Osf2. The transcription repression domain comprises the C-terminal 154 amino acids of Osf2. DNA-binding, domain-swapping, and protein interaction experiments demonstrated that full-length Osf2 does not interact with Cbfβ, a known partner of Runt-related proteins, whereas a deletion mutant of Osf2 containing only the runt and PST domains does. The QA domain appears to be responsible for preventing this heterodimerization. Thus, our results uncover the unique functional organization of Osf2 by identifying functional domains not shared with other Runt-related proteins that largely control its transactivation and heterodimerization abilities.
2
Aronson, B. D., A. L. Fisher, K. Blechman, M. Caudy i J. P. Gergen. "Groucho-dependent and -independent repression activities of Runt domain proteins." Molecular and Cellular Biology 17, nr 9 (wrzesień 1997): 5581–87. http://dx.doi.org/10.1128/mcb.17.9.5581.
Pełny tekst źródłaStreszczenie:
Runt domain proteins are transcriptional regulators that specify cell fates for processes extending from pattern formation in insects to leukemogenesis in humans. Runt domain family members are defined based on the presence of the 128-amino-acid Runt domain, which is necessary and sufficient for sequence-specific DNA binding. We demonstrate an evolutionarily conserved protein-protein interaction between Runt domain proteins and the corepressor Groucho. The interaction, however, is independent of the Runt domain and can be mapped to a 5-amino-acid sequence, VWRPY, present at the C terminus of all Runt domain proteins. Drosophila melanogaster Runt and Groucho interact genetically; the in vivo repression of a subset of Runt-regulated genes is dependent on the interaction with Groucho and is sensitive to Groucho dosage. Runt's repression of one gene, engrailed, is independent of VWRPY and Groucho, thus demonstrating alternative mechanisms for repression by Runt domain proteins. Unlike other transcriptional regulatory proteins that interact with Groucho, Runt domain proteins are known to activate transcription. This suggests that the Runt domain protein-Groucho interaction may be regulated.
3
Golling, G., L. Li, M. Pepling, M. Stebbins i J. P. Gergen. "Drosophila homologs of the proto-oncogene product PEBP2/CBF beta regulate the DNA-binding properties of Runt." Molecular and Cellular Biology 16, nr 3 (marzec 1996): 932–42. http://dx.doi.org/10.1128/mcb.16.3.932.
Pełny tekst źródłaStreszczenie:
The Drosophila runt gene is the founding member of the Runt domain family of transcriptional regulators. Mammalian Runt domain genes encode the alpha subunit of the heterometric DNA-binding factor PEBP2/CBF. The unrelated PEBP2/CBF beta protein interacts with the Runt domain to increase its affinity for DNA. The conserved ability of the Drosophila Runt protein to respond to the stimulating effect of mammalian PEBP2/CBF beta indicated that flies were likely to have a homologous beta protein. Using the yeast two-hybrid system to isolate cDNAs for Runt-interacting proteins, we identified two Drosophila genes, referred to as Brother and Big-brother, that have substantial sequence homology with PEBP2/CBF beta. Yeast two-hybrid experiments as well as in vitro DNA-binding studies confirmed the functional homology of the Brother, Big-brother, and PEBP2/CBF beta proteins and demonstrated that the conserved regions of the Runt and Brother proteins are required for their heterodimeric interaction. The DNA-bending properties of Runt domain proteins in the presence and absence of their partners were also examined. Our results show that Runt domain proteins bend DNA and that this bending is influenced by Brother protein family members, supporting the idea that heterodimerization is associated with a conformational change in the Runt domain. Analysis of expression patterns in Drosophila embryos revealed that Brother and Big-brother are likely to interact with runt in vivo and further suggested that the activity of these proteins is not restricted to their interaction with Runt.
4
Kagoshima, Hiroshi, Katsuya Shigesada, Masanobu Satake, Yoshiaki Ito, Hiroyuki Miyoshi, Misao Ohki, Melissa Pepling i Peter Gergen. "The runt domain identifies a new family of heterometric transcriptional regulators". Trends in Genetics 9, nr 10 (październik 1993): 338–41. http://dx.doi.org/10.1016/0168-9525(93)90026-e.
Pełny tekst źródła
5
Li, L. H., i J. P. Gergen. "Differential interactions between Brother proteins and Runt domain proteins in the Drosophila embryo and eye". Development 126, nr 15 (1.08.1999): 3313–22. http://dx.doi.org/10.1242/dev.126.15.3313.
Pełny tekst źródłaStreszczenie:
Brother and Big brother were isolated as Runt-interacting proteins and are homologous to CBF(beta), which interacts with the mammalian CBF(alpha) Runt-domain proteins. In vitro experiments indicate that Brother family proteins regulate the DNA binding activity of Runt-domain proteins without contacting DNA. In both mouse and human there is genetic evidence that the CBF(alpha) and CBF(beta) proteins function together in hematopoiesis and leukemogenesis. Here we demonstrate functional interactions between Brother proteins and Runt domain proteins in Drosophila. First, we show that a specific point mutation in Runt that disrupts interaction with Brother proteins but does not affect DNA binding activity is dysfunctional in several in vivo assays. Interestingly, this mutant protein acts dominantly to interfere with the Runt-dependent activation of Sxl-lethal transcription. To investigate further the requirements for Brother proteins in Drosophila development, we examine the effects of expression of a Brother fusion protein homologous to the dominant negative CBF(beta)::SMMHC fusion protein that is associated with leukemia in humans. This Bro::SMMHC fusion protein interferes with the activity of Runt and a second Runt domain protein, Lozenge. Moreover, we find that the effects of lozenge mutations on eye development are suppressed by expression of wild-type Brother proteins, suggesting that Brother/Big brother dosage is limiting in this developmental context. Results obtained when Runt is expressed in developing eye discs further support this hypothesis. Our results firmly establish the importance of the Brother and Big brother proteins for the biological activities of Runt and Lozenge, and further suggest that Brother protein function is not restricted to enhancing DNA-binding.
6
Scarpa, Frank J., Madhuri Paul, Rachel Daringer, Sally Agersborg, Vincent A. Funari i Forrest J. Blocker. "Abstract 2281: Molecular profiling of the RUNX1 RUNT domain in myeloid disorders". Cancer Research 82, nr 12_Supplement (15.06.2022): 2281. http://dx.doi.org/10.1158/1538-7445.am2022-2281.
Pełny tekst źródłaStreszczenie:
Abstract Background: AML with RUNX1 mutation is a provisional entity in the WHO classification. RUNX1 variants generally consist of truncating mutations throughout the gene, as well as SNVs, insertions, and deletions in the RUNT domain. In the germline setting, these mutations may lead to familial platelet disorders and have profound implications in donor selection for allogeneic stem cell transplant. Approximately half of mutations in RUNX1 are classified as variants of unknown clinical significance (VOUS), underscoring the unmet needs of this patient population. Methods: Bone marrow, peripheral blood, or FFPE tissue samples from 10,118 patients with suspected myeloid disease were sequenced using a 303 gene myeloid NGS panel. A total of 1209 RUNX1-mutated patients formed the cohort for this study. While pair-matched samples were not available and germline status not established, these patients were likely to be in the 40-60% variant allele frequency (VAF) range. Statistics were performed using Fishers exact test. Results: Among RUNX1-mutated patients, 277 (22.9%) had a RUNX1 variant at a subclonal VAF (<20%), 505 (41.7%), 352 (29.1%), & 75 (6.2%) had variants at VAFs of 20-39%, 40-60%, & >60%, respectively. While all truncating mutations were classified as pathogenic, 84.3% of non-truncating RUNT domain mutations were classified as VOUS. RUNT domain mutations included 272 non-truncating and 220 truncating mutations. There were 599 (49.5%) truncating mutations throughout the entire gene. Non-truncating RUNT domain-mutated patients most frequently harbored mutations in ASXL1 (31.6%), SRSF2 (31.3%), TET2 (29.4%), STAG2 (19.1%), RAS (18.3%), and BCOR/BCORL1 (17.3%). The frequency of RUNT domain co-mutations in the ASXL1 (36.8% [35] vs. 10.4% [5]; p=0.0007) and RAS families (28.4% [26] vs. 10.4% [5]; p=0.03) were significantly higher in the 40-60% VAF group compared to subclonal populations, while BCOR/BCORL1 mutations (10.5% [10] vs. 29.1% [14]; p=0.008) were significantly lower. These results were recapitulated in a cohort of VOUS-only RUNT domain patients with a VAF of 40-60% compared to subclonal populations: ASXL1 (36.8% [21] vs. 22.2% [10]), RAS family (24.5% [14] vs. 10.9% [5]), and BCOR/BCORL1 (8.8% [5] vs. 31.1% [14]; p=0.005). Among patients with truncating mutations in RUNX1, mutations in ASXL1 (34.4% [44] vs 20.3% [42]; p=0.0047) and RAS family members (25.8% [33] vs. 10.1% [21]; p=0.0002) were more frequent in patients with VAFs of 40-60% when compared to subclonal populations, and mutations in BCOR/BCORL1 were similar (28.1% [36] vs. 20.7% [42]). Conclusions: The majority of RUNX1 mutations clustered in the RUNT domain are VOUS. This study demonstrates that both truncations and RUNT domain mutations harbor molecular signatures that reflect similar oncogenic mechanisms. These molecular signatures are also present when filtering exclusively by VOUS in the RUNT domain. Citation Format: Frank J. Scarpa, Madhuri Paul, Rachel Daringer, Sally Agersborg, Vincent A. Funari, Forrest J. Blocker. Molecular profiling of the RUNX1 RUNT domain in myeloid disorders [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2281.
7
Kaminker, Joshua S., Rajan Singh, Tim Lebestky, Huajun Yan i Utpal Banerjee. "Redundant function of Runt Domain binding partners, Big brother and Brother, during Drosophila development". Development 128, nr 14 (15.07.2001): 2639–48. http://dx.doi.org/10.1242/dev.128.14.2639.
Pełny tekst źródłaStreszczenie:
The Core Binding Factor is a heterodimeric transcription factor complex in vertebrates that is composed of a DNA binding α-subunit and a non-DNA binding β-subunit. The α-subunit is encoded by members of the Runt Domain family of proteins and the β-subunit is encoded by the CBFβ gene. In Drosophila, two genes encoding α-subunits, runt and lozenge, and two genes encoding β-subunits, Big brother and Brother, have been previously identified. Here, a sensitized genetic screen was used to isolate mutant alleles of the Big brother gene. Expression studies show that Big brother is a nuclear protein that co-localizes with both Lozenge and Runt in the eye imaginal disc. The nuclear localization and stability of Big brother protein is mediated through the formation of heterodimeric complexes between Big brother and either Lozenge or Runt. Big brother functions with Lozenge during cell fate specification in the eye, and is also required for the development of the embryonic PNS. ds-RNA-mediated genetic interference experiments show that Brother and Big brother are redundant and function together with Runt during segmentation of the embryo. These studies highlight a mechanism for transcriptional control by a Runt Domain protein and a redundant pair of partners in the specification of cell fate during development.
8
Fukushima-Nakase, Yoko, Yoshinori Naoe, Ichiro Taniuchi, Hajime Hosoi, Tohru Sugimoto i Tsukasa Okuda. "Shared and distinct roles mediated through C-terminal subdomains of acute myeloid leukemia/Runt-related transcription factor molecules in murine development". Blood 105, nr 11 (1.06.2005): 4298–307. http://dx.doi.org/10.1182/blood-2004-08-3372.
Pełny tekst źródłaStreszczenie:
Abstract AML1/Runx1 is a frequent target of human leukemia–associated gene aberration and encodes a transcription factor with nonredundant biologic functions in initial development of definitive hematopoiesis, T-cell development, and steady-state platelet production. AML1/Runx1 and 2 closely related family genes, AML2/Runx3 and AML3/Runx2/Cbfa1, present in mammals, comprise the Runt-domain transcription factor family. Although they have similar structural and biochemical properties, gene-targeting experiments have identified distinct biologic roles. To directly determine the presence of functional overlap among runt-related transcription factor (Runx) family molecules, we replaced the C-terminal portion of acute myeloid leukemia 1 (AML1) with that derived from its family members, which are variable in contrast to conserved Runt domain, using the gene knock-in method. We found that C-terminal portions of either AML2 or AML3 could functionally replace that of AML1 for myeloid development in culture and within the entire mouse. However, while AML2 substituted for AML1 could effectively rescue lymphoid lineages, AML3 could not, resulting in a smaller thymus and lymphoid deficiency in peripheral blood. Substitution by the C-terminal portion of AML3 also led to high infantile mortality and growth retardation, suggesting that AML1 has as yet unidentified effects on these phenotypes. Thus, the C-terminal portions of Runx family members have both similar and distinct biologic functions.
9
Mahadeveraju, Sharvani, Young-Ho Jung i James W. Erickson. "Evidence That Runt Acts as a Counter-Repressor of Groucho During Drosophila melanogaster Primary Sex Determination". G3: Genes|Genomes|Genetics 10, nr 7 (26.05.2020): 2487–96. http://dx.doi.org/10.1534/g3.120.401384.
Pełny tekst źródłaStreszczenie:
Runx proteins are bifunctional transcription factors that both repress and activate transcription in animal cells. Typically, Runx proteins work in concert with other transcriptional regulators, including co-activators and co-repressors to mediate their biological effects. In Drosophila melanogaster the archetypal Runx protein, Runt, functions in numerous processes including segmentation, neurogenesis and sex determination. During primary sex determination Runt acts as one of four X-linked signal element (XSE) proteins that direct female-specific activation of the establishment promoter (Pe) of the master regulatory gene Sex-lethal (Sxl). Successful activation of SxlPe requires that the XSE proteins overcome the repressive effects of maternally deposited Groucho (Gro), a potent co-repressor of the Gro/TLE family. Runx proteins, including Runt, contain a C-terminal peptide, VWRPY, known to bind to Gro/TLE proteins to mediate transcriptional repression. We show that Runt’s VWRPY co-repressor-interaction domain is needed for Runt to activate SxlPe. Deletion of the Gro-interaction domain eliminates Runt-ability to activate SxlPe, whereas replacement with a higher affinity, VWRPW, sequence promotes Runt-mediated transcription. This suggests that Runt may activate SxlPe by antagonizing Gro function, a conclusion consistent with earlier findings that Runt is needed for Sxl expression only in embryonic regions with high Gro activity. Surprisingly we found that Runt is not required for the initial activation of SxlPe. Instead, Runt is needed to keep SxlPe active during the subsequent period of high-level Sxl transcription suggesting that Runt helps amplify the difference between female and male XSE signals by counter-repressing Gro in female, but not in male, embryos.
10
Cheney, Matthew D., Yizhou Liu, Yunpeng Zhou, Maksymilian Chruszcz, Thomas M. Laue, Wladek Minor, John H. Bushweller i Nancy A. Speck. "Structural and Functional Characterization of the NHR2 and Runt Domains of AML1/ETO." Blood 104, nr 11 (16.11.2004): 482. http://dx.doi.org/10.1182/blood.v104.11.482.482.
Pełny tekst źródłaStreszczenie:
Abstract AML1/ETO is the chimeric fusion protein resulting from the t(8;21) found in AML of the M2 subtype. It contains the N-terminal 177 amino acids of RUNX1 and virtually all (575aa) of ETO. The RUNX1 component includes the Runt domain, which mediates both DNA binding and heterodimerization with CBFβ, but lacks the more C-terminal sequences required for transactivation. AML1/ETO occupies RUNX target genes in vivo and is associated with a repressive chromatin structure characterized by reduced levels of acetylated histone H3. AML1/ETO is thought to repress transcription by recruiting a SMRT (N-CoR)/Sin3A/HDAC complex to chromatin via sequences in ETO. ETO is the human homologue of the Drosophila Nervy protein and shares 4 regions of homology with Nervy called Nervy Homology Regions (NHR) 1–4. Deletion studies have shown that three of the AML1/ETO domains essential for its repressive function are the Runt domain, NHR2, and NHR4. The NHR2 domain is a hydrophobic heptad repeat that mediates oligomerization of AML1/ETO, interaction with ETO family members, and also with mSin3A and HDACs. We recently solved an x-ray structure of the NHR2 domain and found it to be an alpha-helical tetramer. Based on this structure we have introduced amino acid substitutions into the NHR2 domain that disrupt tetramer formation but not AML1/ETO stability. These mutations impair the ability of AML1/ETO to inhibit the differentiation of GR-1+/Mac-1+ cells following retroviral transduction into primary mouse bone marrow cells, and also inhibit the serial replating ability of AML1/ETO expressing bone marrow cells in vitro. We additionally show that mutations reported by Amann et al. (Mol Cell Biol. 21, 6470, 2001) to disrupt mSin3A binding to NHR2 do not affect the biological activity of AML1/ETO in vitro. We also introduced mutations in the Runt domain of AML1/ETO that disrupt CBFβ binding by defined amounts (40-fold, 200-fold, 500-fold), and demonstrated that CBFβ binding by AML1/ETO is essential for its dominant negative activity. The latter results suggest that small molecules designed to selectively impair heterodimerization of AML1/ETO with CBFβ could potentially block AML1/ETO’s dominant negative activity.
11
Osato, Motomi, Norio Asou, Essam Abdalla, Koyu Hoshino, Hiroshi Yamasaki, Toshiya Okubo, Hitoshi Suzushima i in. "Biallelic and Heterozygous Point Mutations in the Runt Domain of theAML1/PEBP2B Gene Associated With Myeloblastic Leukemias". Blood 93, nr 6 (15.03.1999): 1817–24. http://dx.doi.org/10.1182/blood.v93.6.1817.406k36_1817_1824.
Pełny tekst źródłaStreszczenie:
The AML1 gene encoding the DNA-binding -subunit in the Runt domain family of heterodimeric transcription factors has been noted for its frequent involvement in chromosomal translocations associated with leukemia. Using reverse transcriptase-polymerase chain reaction (RT-PCR) combined with nonisotopic RNase cleavage assay (NIRCA), we found point mutations of the AML1 gene in 8 of 160 leukemia patients: silent mutations, heterozygous missense mutations, and biallelic nonsense or frameshift mutations in 2, 4, and 2 cases, respectively. The mutations were all clustered within the Runt domain. Missense mutations identified in 3 patients showed neither DNA binding nor transactivation, although being active in heterodimerization. These defective missense mutants may be relevant to the predisposition or progression of leukemia. On the other hand, the biallelic nonsense mutants encoding truncated AML1 proteins lost almost all functions examined and may play a role in leukemogenesis leading to acute myeloblastic leukemia.
12
Ahn, Mee-Young, Suk-Chul Bae, Mitsuo Maruyama i Yoshiaki Ito. "Comparison of the human genomic structure of the Runt domain-encoding PEBP2/CBFα gene family". Gene 168, nr 2 (styczeń 1996): 279–80. http://dx.doi.org/10.1016/0378-1119(95)00751-2.
Pełny tekst źródła
13
Walrad, Pegine B., Saiyu Hang, Genevieve S. Joseph, Julia Salas i J. Peter Gergen. "Distinct Contributions of Conserved Modules to Runt Transcription Factor Activity". Molecular Biology of the Cell 21, nr 13 (lipiec 2010): 2315–26. http://dx.doi.org/10.1091/mbc.e09-11-0953.
Pełny tekst źródłaStreszczenie:
Runx proteins play vital roles in regulating transcription in numerous developmental pathways throughout the animal kingdom. Two Runx protein hallmarks are the DNA-binding Runt domain and a C-terminal VWRPY motif that mediates interaction with TLE/Gro corepressor proteins. A phylogenetic analysis of Runt, the founding Runx family member, identifies four distinct regions C-terminal to the Runt domain that are conserved in Drosophila and other insects. We used a series of previously described ectopic expression assays to investigate the functions of these different conserved regions in regulating gene expression during embryogenesis and in controlling axonal projections in the developing eye. The results indicate each conserved region is required for a different subset of activities and identify distinct regions that participate in the transcriptional activation and repression of the segmentation gene sloppy-paired-1 (slp1). Interestingly, the C-terminal VWRPY-containing region is not required for repression but instead plays a role in slp1 activation. Genetic experiments indicating that Groucho (Gro) does not participate in slp1 regulation further suggest that Runt's conserved C-terminus interacts with other factors to promote transcriptional activation. These results provide a foundation for further studies on the molecular interactions that contribute to the context-dependent properties of Runx proteins as developmental regulators.
14
Cheney, Matthew D., Yizhou Liu, Justin J. Gaudet, Maksymilian Chruszcz, Stephen M. Lukasik, Daisuke Sugiyama, Jeff Lary i in. "Structural and Functional Characterization of the NHR2 and Runt Domains of AML1/ETO." Blood 106, nr 11 (16.11.2005): 2854. http://dx.doi.org/10.1182/blood.v106.11.2854.2854.
Pełny tekst źródłaStreszczenie:
Abstract AML1/ETO is the chimeric fusion protein resulting from the t(8;21) found in AML of the M2 subtype. It contains the N-terminal 177 amino acids of RUNX1 and virtually all (575aa) of ETO. The RUNX1 component includes the Runt domain, which mediates both DNA binding and heterodimerization with CBFβ, but lacks the more C-terminal sequences required for transactivation. AML1/ETO occupies RUNX target genes in vivo and is associated with a repressive chromatin structure characterized by reduced levels of acetylated histone H3. AML1/ETO is thought to repress transcription by recruiting a SMRT (N-CoR)/Sin3A/HDAC complex to chromatin via sequences in ETO. ETO is the human homologue of the Drosophila Nervy protein and shares 4 regions of homology with Nervy called Nervy Homology Regions (NHR) 1–4. Deletion studies have shown that three of the AML1/ETO domains essential for its repressive function are the Runt domain, NHR2, and NHR4. The NHR2 domain is a hydrophobic heptad repeat that mediates oligomerization of AML1/ETO, interaction with ETO family members, and also with mSin3A and HDACs. We recently solved an x-ray structure of the NHR2 domain and found it to be an alpha-helical tetramer. Based on this structure we have introduced amino acid substitutions into the NHR2 domain that disrupt tetramer formation but not AML1/ETO stability. These mutations impair the ability of AML1/ETO to inhibit the differentiation of GR−1+/Mac−1+ cells following retroviral transduction into primary mouse bone marrow cells, and also inhibit the serial replating ability of AML1/ETO expressing bone marrow cells in vitro. We also assessed the outcome of disrupting oligomerization on a variety of previously described protein-protein interactions, and found that neither deleting the NHR2 domain nor disrupting oligomerization affected the ability of HDAC1, HDAC2, HDAC3, N-CoR, SMRT, PKA RIIα, PLZF, or HEB, to co-immunoprecipitate AML1/ETO from cell extracts. Deletion of the NHR2 domain reduced binding of mSin3a as shown previously, but disruption of oligomerization did not. To investigate the contribution of oligomerization to AML1/ETO-mediated transcriptional modulation, we amplified RNA from retrovirally-transduced, lineage depleted primary mouse bone marrow cells and performed Real Time Quantitative PCR of genes whose expression is known to be regulated by AML1/ETO or RUNX1. We show that the requirement for oligomerization is target gene dependent, with several classes of genes resulting from our study. We also introduced mutations in the Runt domain of AML1/ETO that disrupt CBFβ binding by defined amounts (40-fold, 200-fold, 500-fold), and demonstrated that CBFβ binding by AML1/ETO is essential for its dominant negative activity. The latter results suggest that small molecules designed to selectively impair heterodimerization of AML1/ETO with CBFβ could potentially block AML1/ETO’s dominant negative activity.
15
Sugiyama, Daisuke, Hiroko Sugiyama i Nancy A. Speck. "A Role for Twist in Thymocyte Development." Blood 106, nr 11 (16.11.2005): 4252. http://dx.doi.org/10.1182/blood.v106.11.4252.4252.
Pełny tekst źródłaStreszczenie:
Abstract Twist-1 and Twist-2 are basic helix-loop-helix (bHLH)- containing transcription factors important for mesoderm and muscle formation, and for osteoblast differentiation. The Twist proteins were previously shown to interact both physically and genetically with Runx2, a member of the core binding factor family of transcription factors (Bialek et al. Dev. Cell6: 423, 2004). Twist-1 and Twist-2 transiently inhibit Runx2 function during bone formation by inhibiting DNA binding by the Runx2 Runt domain. Since the Runt domains of the core binding factors are highly conserved, this raised the possibility that the Twist proteins may also regulate Runx1 function in hematopoiesis. To address this hypothesis we used Charlie Chaplin (CC) mice, which contain a hypomorphic Twist-1 allele generated by N-ethyl-N-nitrosourea (ENU) mutagenesis (Justice, Nat. Rev. Genet.1: 109, 2000). The CC allele encodes a single amino acid substitution (Ser192Pro) in the Twist box of Twist-1, which normally interacts with the Runt domain. CC/CC mice die from an unknown cause shortly after birth, and have small thymuses. No other hematopoietic organs show significant differences in cellularity. The number of bone marrow hematopoietic progenitors is almost identical among CC/CC, CC/+, and +/+ littermates as assessed by flowcytometry and colony forming assays. The ratios of CD4/CD8 single positive cells, and DN1-4 thymocytes are unperturbed, suggesting that T cell maturation is normal in CC/CC fetuses. However, CC/CC thymuses are reconstituted by wild type bone marrow at a lower efficiency than are wild type thymuses in fetal thymus organ culture assays, suggesting that Twist-1 may have an important non-cell autonomous role in thymocyte development.
16
Gu, Ting-Lei, Tamara L. Goetz, Barbara J. Graves i Nancy A. Speck. "Auto-Inhibition and Partner Proteins, Core-Binding Factor β (CBFβ) and Ets-1, Modulate DNA Binding by CBFα2 (AML1)". Molecular and Cellular Biology 20, nr 1 (1.01.2000): 91–103. http://dx.doi.org/10.1128/mcb.20.1.91-103.2000.
Pełny tekst źródłaStreszczenie:
ABSTRACT Core-binding factor α2 (CBFα2; otherwise known as AML1 or PEBP2αB) is a DNA-binding subunit in the family of core-binding factors (CBFs), heterodimeric transcription factors that play pivotal roles in multiple developmental processes in mammals, including hematopoiesis and bone development. The Runt domain in CBFα2 (amino acids 51 to 178) mediates DNA binding and heterodimerization with the non-DNA-binding CBFβ subunit. Both the CBFβ subunit and the DNA-binding protein Ets-1 stimulate DNA binding by the CBFα2 protein. Here we quantify and compare the extent of cooperativity between CBFα2, CBFβ, and Ets-1. We also identify auto-inhibitory sequences within CBFα2 and sequences that modulate its interactions with CBFβ and Ets-1. We show that sequences in the CBFα2 Runt domain and sequences C terminal to amino acid 214 inhibit DNA binding. Sequences C terminal to amino acid 214 also inhibit heterodimerization with the non-DNA-binding CBFβ subunit, particularly heterodimerization off DNA. CBFβ rescinds the intramolecular inhibition of CBFα2, stimulating DNA binding approximately 40-fold. In comparison, Ets-1 stimulates CBFα2 DNA binding 7- to 10-fold. Although the Runt domain alone is sufficient for heterodimerization with CBFβ, sequences N terminal to amino acid 41 and between amino acids 190 and 214 are required for cooperative DNA binding with Ets-1. Cooperative DNA binding with Ets-1 is less pronounced with the CBFα2-CBFβ heterodimer than with CBFα2 alone. These analyses demonstrate that CBFα2 is subject to both negative regulation by intramolecular interactions, and positive regulation by two alternative partnerships.
17
Nielsen, Alek d., Sayer Alharbi, Cassandra M. Hirsch, Bartlomiej P. Przychodzen, Mikkael A. Sekeres, Yogen Saunthararajah, Hetty E. Carraway i Jaroslaw P. Maciejewski. "Germline Variants of RUNX-1 in Myeloid Malignancy". Blood 128, nr 22 (2.12.2016): 3926. http://dx.doi.org/10.1182/blood.v128.22.3926.3926.
Pełny tekst źródłaStreszczenie:
Abstract Mutation of the master transcription factor RUNX1 (NM_001754) has a well characterized role in the pathogenesis of myeloid neoplasms. RUNX1 is located at 21q22 and is composed of a c-terminal transactivation domain (TAD) (269-480) and an n-terminal RUNT domain (amino acid 76-209) that binds DNA and mediates heterodimerization with CBF-β. If the RUNT domain is disrupted a RUNX1 mutant will behave in a dominant negative fashion. Mutations leaving the RUNT domain intact result in haploinsufficiency compounded by CBF-β binding site competition with the wild-type allele. Germline (GL) RUNX1 mutations cause the autosomal dominant predisposition syndrome familial platelet disorder with propensity to myeloid malignancy (FPDMM). In FPDMM, RUNX1 mutations, including RUNT domain missense mutations or nonsense mutations throughout the gene, confer mild chronic platelet disorders and a lifetime risk of MDS/AML. As with other GL predisposition syndromes a secondary event is considered necessary for progression, typically an additional mutation in the wild type RUNX1 allele. Onset of MDS/AML occurs at a median age of 33 years but the latency can be variable and ease of detection in younger cases likely distorts summary statistics. Inherited mutations in adults may be difficult to distinguish and have not been systematically explored. We hypothesize that a fraction of patients with otherwise typical RUNX1-positive MDS or related disorders are in fact carriers of a RUNX1 GL mutation. DNA obtained from a cohort of 1451 patients with myeloid neoplasia was analyzed using a multiamplicon deep next-generation sequencing (NGS) panel including all ORFs of RUNX1. A total of 124 patients (8.5%) were found to carry 117 unique RUNX1 mutations. Of these, 59 hits were missense and 58 nonsense; and in 94 (76%) of cases the RUNT domain was disrupted. Eighteen (15.3% RUNX1 positive patients) were previously described in FPDMM. We applied various bio analytic criteria to designate somatic status in 57 patients. The remaining 64 RUNX1 mutations were further investigated, when possible, by paired capillary sequencing of CD3- mononuclear DNA and in-vitro expanded CD3+ T-Cell DNA. We found 5/31 (16%) of these cases carried mutation in both myeloid and lymphoid lineages and were designated GL. This included 2 post-RUNT truncations (p.Y281*, p.S410*) and two RUNT domain missense mutations (p.R80C, p.S141L) all of which are expected to produce a dominant negative phenotype. A 5th GL mutation of uncertain significance in the TAD (p.M310I) was also discovered. Excluding this TAD missense mutation, each of these have been described as somatic factors in myeloid disease. The truncation at amino acid 410 is further downstream than all reported FPDMM variants to date. Chart review revealed an anamnestic presence of thrombocytopenia in 80% of proposed FPD patients. Suggestive family history was found in both truncated cases, with hematologic malignancy presenting in a 1st degree relative before 30 years of age. Median age at diagnosis of MDS/AML in GL cases was 46 years (range: 18-68 years) compared to 65 years in the cases designated somatic (range: 37-87 years). Two cases (p.S410* and p.M310I) had cytogenetic abnormalities on the 21st chromosome (trisomy 21 and t(8;21) respectively) and had no other molecular abnormalities detected by our NGS panel. A mutation in GPR98 of unknown significance was found with p.Y281*. Lastly the p.S141L mutant had cooperating mutations in chromatin modifiers ASXL1 and BCOR, and in RNA splicing gene LUC7L2. This study of an exemplary GL leukemia gene suggests that systematic searches for known and potential GL predisposition genes in otherwise typical adult cohorts may reveal a GL role in the evolution of myeloid neoplasms. Future work to determine genetic predisposition to leukemia in adults is essential. Disclosures Sekeres: Celgene: Membership on an entity's Board of Directors or advisory committees; Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees. Carraway:Celgene: Research Funding, Speakers Bureau; Baxalta: Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees.
18
Levanon, D., V. Negreanu, Y. Bernstein, I. Bar-Am, L. Avivi i Y. Groner. "AML1, AML2, and AML3, the Human Members of the runt domain Gene-Family: cDNA Structure, Expression, and Chromosomal Localization". Genomics 23, nr 2 (wrzesień 1994): 425–32. http://dx.doi.org/10.1006/geno.1994.1519.
Pełny tekst źródła
19
Buijs, Arjan, Pino Poddighe, Richard van Wijk, Wouter van Solinge, Eric Borst, Leo Verdonck, Anton Hagenbeek, Peter Pearson i Henk Lokhorst. "A novel CBFA2 single-nucleotide mutation in familial platelet disorder with propensity to develop myeloid malignancies". Blood 98, nr 9 (1.11.2001): 2856–58. http://dx.doi.org/10.1182/blood.v98.9.2856.
Pełny tekst źródłaStreszczenie:
Abstract Hereditary mutations associated with hematologic malignancies are rare. Heterozygous mutations affecting the hematopoietic transcription factor CBFA2 (also AML1/RUNX1) were recently reported to be associated with familial platelet disorder with predisposition to acute myeloid leukemia (FPD/AML, MIM 601399). A new 3-generation family with FPD/AML with a novel CBFA2 mutation is described. In this family, AML was diagnosed in a second-generation male. After allogeneic stem cell transplantation from his human leukocyte antigen–identical sister, a donor-derived, genetically identical leukemia developed in the recipient and the donor. Sequencing analysis identified a G-to-T transition within the CBFA2 gene, which involves codon 198, encoding a conserved aspartic acid within the DNA- binding Runt domain. Three of 5 siblings affected with the FPD/AML trait harbored the mutation in a heterozygous form. This experience underscores the necessity of performing mutation analysis of the CBFA2 gene before sibling allogeneic transplantation in families with FPD/AML.
20
Song, Xiaorui, Ying Song, Miren Dong, Zhaoqun Liu, Weilin Wang, Lingling Wang i Linsheng Song. "A new member of the runt domain family from Pacific oyster Crassostrea gigas (CgRunx) potentially involved in immune response and larvae hematopoiesis". Fish & Shellfish Immunology 89 (czerwiec 2019): 228–36. http://dx.doi.org/10.1016/j.fsi.2019.03.066.
Pełny tekst źródła
21
Wang, Kainan, Cindy Degerny, Minghong Xu i Xiang-Jiao Yang. "YAP, TAZ, and Yorkie: a conserved family of signal-responsive transcriptional coregulators in animal development and human diseaseThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB’s 51st Annual Meeting – Epigenetics and Chromatin Dynamics, and has undergone the Journal’s usual peer review process." Biochemistry and Cell Biology 87, nr 1 (luty 2009): 77–91. http://dx.doi.org/10.1139/o08-114.
Pełny tekst źródłaStreszczenie:
How extracellular cues are transduced to the nucleus is a fundamental issue in biology. The paralogous WW-domain proteins YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif; also known as WWTR1, for WW-domain containing transcription regulator 1) constitute a pair of transducers linking cytoplasmic signaling events to transcriptional regulation in the nucleus. A cascade composed of mammalian Ste20-like (MST) and large tumor suppressor (LATS) kinases directs multisite phosphorylation, promotes 14-3-3 binding, and hinders nuclear import of YAP and TAZ, thereby inhibiting their transcriptional coactivator and growth-promoting activities. A similar cascade regulates the trafficking and function of Yorkie, the fly orthologue of YAP. Mammalian YAP and TAZ are expressed in various tissues and serve as coregulators for transcriptional enhancer factors (TEFs; also referred to as TEADs, for TEA-domain proteins), runt-domain transcription factors (Runxs), peroxisome proliferator-activated receptor γ (PPARγ), T-box transcription factor 5 (Tbx5), and several others. YAP and TAZ play distinct roles during mouse development. Both, and their upstream regulators, are intimately linked to tumorigenesis and other pathogenic processes. Here, we review studies on this family of signal-responsive transcriptional coregulators and emphasize how relative sequence conservation predicates their function and regulation, to provide a conceptual framework for organizing available information and seeking new knowledge about these signal transducers.
22
Berardi, Marcelo J., Chaohong Sun, Michael Zehr, Frits Abildgaard, Jeff Peng, Nancy A. Speck i John H. Bushweller. "The Ig fold of the core binding factor α Runt domain is a member of a family of structurally and functionally related Ig-fold DNA-binding domains". Structure 7, nr 10 (październik 1999): 1247–56. http://dx.doi.org/10.1016/s0969-2126(00)80058-1.
Pełny tekst źródła
23
Bruno, Ludovica, Luca Mazzarella, Maarten Hoogenkamp, Arnulf Hertweck, Bradley S. Cobb, Stephan Sauer, Suzana Hadjur i in. "Runx proteins regulate Foxp3 expression". Journal of Experimental Medicine 206, nr 11 (19.10.2009): 2329–37. http://dx.doi.org/10.1084/jem.20090226.
Pełny tekst źródłaStreszczenie:
Runx proteins are essential for hematopoiesis and play an important role in T cell development by regulating key target genes, such as CD4 and CD8 as well as lymphokine genes, during the specialization of naive CD4 T cells into distinct T helper subsets. In regulatory T (T reg) cells, the signature transcription factor Foxp3 interacts with and modulates the function of several other DNA binding proteins, including Runx family members, at the protein level. We show that Runx proteins also regulate the initiation and the maintenance of Foxp3 gene expression in CD4 T cells. Full-length Runx promoted the de novo expression of Foxp3 during inducible T reg cell differentiation, whereas the isolated dominant-negative Runt DNA binding domain antagonized de novo Foxp3 expression. Foxp3 expression in natural T reg cells remained dependent on Runx proteins and correlated with the binding of Runx/core-binding factor β to regulatory elements within the Foxp3 locus. Our data show that Runx and Foxp3 are components of a feed-forward loop in which Runx proteins contribute to the expression of Foxp3 and cooperate with Foxp3 proteins to regulate the expression of downstream target genes.
24
Zhang, Xiuli, Yining Li, Pingzhen Yang, Xiaoyu Liu, Lihe Lu, Yanting Chen, Xinglong Zhong i in. "Trimethylamine-N-Oxide Promotes Vascular Calcification Through Activation of NLRP3 (Nucleotide-Binding Domain, Leucine-Rich-Containing Family, Pyrin Domain-Containing-3) Inflammasome and NF-κB (Nuclear Factor κB) Signals". Arteriosclerosis, Thrombosis, and Vascular Biology 40, nr 3 (marzec 2020): 751–65. http://dx.doi.org/10.1161/atvbaha.119.313414.
Pełny tekst źródłaStreszczenie:
Objectives: Vascular calcification is highly prevalent in patients with chronic kidney disease. Increased plasma trimethylamine N-oxide (TMAO), a gut microbiota-dependent product, concentrations are found in patients undergoing hemodialysis. However, a clear mechanistic link between TMAO and vascular calcification is not yet established. In this study, we investigate whether TMAO participates in the progression of vascular calcification using in vitro, ex vivo, and in vivo models. Approach and Results: Alizarin red staining revealed that TMAO promoted calcium/phosphate-induced calcification of rat and human vascular smooth muscle cells in a dose-dependent manner, and this was confirmed by calcium content assay. Similarly, TMAO upregulated the expression of bone-related molecules including Runx2 (Runt-related transcription factor 2) and BMP2 (bone morphogenetic protein-2), suggesting that TMAO promoted osteogenic differentiation of vascular smooth muscle cells. In addition, ex vivo study also showed the positive regulatory effect of TMAO on vascular calcification. Furthermore, we found that TMAO accelerated vascular calcification in rats with chronic kidney disease, as indicated by Mico-computed tomography analysis, alizarin red staining and calcium content assay. By contrast, reducing TMAO levels by antibiotics attenuated vascular calcification in chronic kidney disease rats. Interestingly, TMAO activated NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3) inflammasome and NF-κB (nuclear factor κB) signals during vascular calcification. Inhibition of NLRP3 inflammasome and NF-κB signals attenuated TMAO-induced vascular smooth muscle cell calcification. Conclusions: This study for the first time demonstrates that TMAO promotes vascular calcification through activation of NLRP3 inflammasome and NF-κB signals, suggesting the potential link between gut microbial metabolism and vascular calcification. Reducing the levels of TMAO could become a potential treatment strategy for vascular calcification in chronic kidney disease.
25
Spender, Lindsay C., Georgina H. Cornish, Alexandra Sullivan i Paul J. Farrell. "Expression of Transcription Factor AML-2 (RUNX3, CBFα-3) Is Induced by Epstein-Barr Virus EBNA-2 and Correlates with the B-Cell Activation Phenotype". Journal of Virology 76, nr 10 (15.05.2002): 4919–27. http://dx.doi.org/10.1128/jvi.76.10.4919-4927.2002.
Pełny tekst źródłaStreszczenie:
ABSTRACT To identify cell proteins regulated by the Epstein-Barr virus (EBV) transcription factor EBNA-2, we analyzed a cell line with conditional EBNA-2 activity by using microarray expression profiling. This led to the identification of two novel target genes induced by EBNA-2. The first of these, interleukin-16, is an immunomodulatory cytokine involved in the regulation of CD4 T cells. The second, AML-2, is a member of the Runt domain family of transcription factors. Quiescent B cells initially expressed AML-1 but, 48 h after virus infection, the levels of AML-1 decreased dramatically, whereas the amount of AML-2 protein increased. Analysis of a panel of B-cell lines indicated that AML-2 expression is normally predominant in EBV latency III, whereas AML-1 is associated with EBV latency I or EBV-negative cells. The AML genes are the first example of cell transcription factors whose expression correlates with the latency I/III phenotype.
26
Akamatsu, Yoshiko, Shin-ichi Tsukumo, Hiroshi Kagoshima, Naoya Tsurushita i Katsuya Shigesada. "A simple screening for mutant DNA binding proteins: application to murine transcription factor PEBP2α subunit, a founding member of the Runt domain protein family". Gene 185, nr 1 (styczeń 1997): 111–17. http://dx.doi.org/10.1016/s0378-1119(96)00644-0.
Pełny tekst źródła
27
Masuda, Tatsuya, Hirohito Kubota, Naoya Sakuramoto, Asuka Hada, Ayaka Horiuchi, Asami Sasaki, Kanako Takeda i in. "RUNX-NFAT Axis As a Novel Therapeutic Target for AML and T Cell Immunity". Blood 136, Supplement 1 (5.11.2020): 25–26. http://dx.doi.org/10.1182/blood-2020-143458.
Pełny tekst źródłaStreszczenie:
Runt-related transcription factor (RUNX) transcription factors are essential regulators of diverse developmental processes. In mammals, there are three RUNX genes, RUNX1, RUNX2, and RUNX3. All RUNX proteins contain a highly conserved DNA-binding domain, called the runt-homology domain (RHD), which is responsible for DNA-binding and interaction with a partner, core binding factor subunit β (CBFβ). They regulate transcription of target genes, involving hematopoietic differentiation, cell cycle regulation, p53 pathways, and so on. From our previous studies, we assume that compensation mechanism is present among the RUNX family members. RUNX plays pivotal roles in leukemogenesis and inhibition of RUNX has now been widely recognized as a novel strategy in anti-leukemic therapies. However, common mechanism via RUNX in diverse acute myeloid leukemia (AML) remains elusive. Here, we demonstrate that targeting RUNX-nuclear factor of activated T cells 2 (NFATC2) axis is an effective strategy to suppress drug-resistant (DR)-acute promyelocytic leukemia (APL) cells. Silencing of RUNX and NFATC2 in DR-APL cells suppressed cell growth and induced apoptotic cell death. Next, by RNA-seq analysis of several AML patient cohorts, we confirmed that a strong positive correlation between RUNX family (RUNX1,2,3: Pan RUNX) and NFAT family (NFATC1,2,3,4, NFAT5: Pan NFAT) exists not only in APL but also in all hematopoietic malignancies and that AML forms the Pan RUNX high-Pan NFAT high expression cluster. Inspection of the NFATC1-3 promoter revealed the RUNX binding sequence, and direct transcriptionally regulation of NFATC1-3 by RUNX family was confirmed in both chromatin immunoprecipitation (ChIP)-seq analysis and dual luciferase reporter assay. We believe that RUNX-NFAT axis could be an important target in diverse AML. Next, considering the well-established role of RUNX and NFATC2 in T cell immunity, we also apply targeting RUNX-NFATC2 strategy to suppress T cell activation and xenogeneic graft-versus-host disease (GVHD).The expansion of donor T cells requires IL-2, and aGVHD has been defined as a Th1-mediated disease. It is now well known that RUNX, especially RUNX1 and RUNX3 , are highly expressed in T cells, and directly regulate Th1 cytokine genes. As immunosuppressive approach for the prevention or treatment of aGVHD, calcineurin inhibitors, cyclosporine A and tacrolimus, inhibit GVHD by preventing the activation of NFAT, and steroid inhibits transcription of proinflammatory genes. We suppose that targeting RUNX can downregulate NFAT and also cytokine genes in T cell. RUNX1 knockdown and PanRUNX knockdown led to deceased NFATC2 and cytokine gene expression in cytokine-producing Jurkat cell line. It was also confirmed that by inhibiting the RUNX family and suppressing the NFATC2 family at the transcriptional level, the amount of the total NFATC family was significantly reduced compared with the drug that suppresses the nuclear translocation of NFATc2.The importance of RUNX-NFATC2 axis in T cell immunity was also exactly confirmed by the rescue experiments. Finally, to achieve "cluster regulation of RUNX (CROX)" strategy, we have been developing a novel RUNX inhibitor: chlorambucil-conjugated pyrrole-imidazole (PI) polyamides (Chb-M') that targets consensus RUNX-binding sequences, and specifically inhibits binding of RUNX family members. So, Chb-M' can switch off the RUNX target genes efficiently. In diverse AML including APL, core binding factor (CBF)-AML, mixed lineage leukemia (MLL)-rearranged AML, and AML-M0 and so on, Chb-M' was remarkably effective, and suppressed the expression of NFAT family in the protein level and induced apoptotic cell death. ChbM' also had a prominent effect in the AMLPDX model.The importance of RUNX-NFAT axis in AML was confirmed by the pharmacological rescue experiments using phorbol 12-myristate 13-acetate (PMA) and Ionomycin stimulation. Chb-M' also suppressed NFATC2 and cytokine gene expression in peripheral blood mononuclear cells (PBMC) and ameliorated GVHD for xenogeneic GVHD mouse model by transplanting human PBMC into immunodeficient mice. Taken together, we show RUNX could be a novel therapeutic target against diverse AML and GVHD through targeting RUNX-NFAT axis. Disclosures No relevant conflicts of interest to declare.
28
Yamaguchi, Akira, Toshihisa Komori i Tatsuo Suda. "Regulation of Osteoblast Differentiation Mediated by Bone Morphogenetic Proteins, Hedgehogs, and Cbfa1". Endocrine Reviews 21, nr 4 (1.08.2000): 393–411. http://dx.doi.org/10.1210/edrv.21.4.0403.
Pełny tekst źródłaStreszczenie:
Abstract Osteoblasts arise from common progenitors with chondrocytes, muscle and adipocytes, and various hormones and local factors regulate their differentiation. We review here regulation of osteoblast differentiation mediated by the local factors such as bone morphogenetic proteins (BMPs) and hedgehogs and the transcription factor, core-binding factor α-1 (Cbfa1). BMPs are the most potent regulators of osteoblast differentiation among the local factors. Sonic and Indian hedgehogs are involved in osteoblast differentiation by interacting with BMPs. Cbfa1, a member of the runt domain gene family, plays a major role in the processes of a determination of osteoblast cell lineage and maturation of osteoblasts. Cbfa1 is an essential transcription factor for osteoblast differentiation and bone formation, because Cbfa1-deficient mice completely lacked bone formation due to maturation arrest of osteoblasts. Although the regulatory mechanism of Cbfa1 expression has not been fully clarified, BMPs are an important local factor that up-regulates Cbfa1 expression. Thus, the intimate interaction between local factors such as BMPs and hedgehogs and the transcription factor, Cbfa1, is important to osteoblast differentiation and bone formation.
29
Alkadi, Halah, David McKellar, Tao Zhen, Tatiana Karpova, Lisa J. Garrett, Yongxing Gao, Anfal A. Alsadhan i in. "The VWRPY Domain Is Essential for RUNX1 Function in Hematopoietic Progenitor Cell Maturation and Megakaryocyte Differentiation". Blood 132, Supplement 1 (29.11.2018): 1319. http://dx.doi.org/10.1182/blood-2018-99-113400.
Pełny tekst źródłaStreszczenie:
Abstract RUNX1 is a transcription factor essential during definitive hematopoiesis. Germline mutations in RUNX1 results in a disorder called Familial Platelet Disorder with Associated Myeloid Malignancy (FPDMM). FPDMM patients have abnormal bleeding due to reduced platelet count and/or function. Importantly, 20-60% of the FPDMM patients develop hematological malignancies, which are mainly myeloid. Reported RUNX1 mutations in FPDMM families are mostly clustered in the N-terminal runt domain and the C-terminal transactivation domain. Recently, three mutations have been reported at or near the end of the C-terminal repression domain, the VWRPY motif. However, the mechanism behind the VWRPY motif involvement in the FPDMM pathogenesis has not been studied. Interestingly, these VWRPY-mutated RUNX1 proteins still have intact runt and transactivation domains, but patients still show FPDMM phenotype. Here, we evaluate the functional defects of a RUNX1 mutation, L472fsX, which was reported in a FPDMM family, using three different experimental models. Our study is aimed to unravel the significance of the VWRPY motif in FPDMM pathogenesis. The RUNX1 L472fsX mutation is caused by a GC insertion upstream of the VWRPY motif. The mutation results in a frameshift and a run on protein for an additional 123 amino acids. The frameshift abolishes the VWRPY motif, which is responsible for the binding between RUNX1 and a co-repressor protein, TLE1. As expected, from both FRET and co-IP assays, the mutated RUNX1 lost binding with TLE1. Interestingly, we observed increased binding between the mutated RUNX1 and its co-factor CBFβ in the FRET assay, as compared to the wildtype RUNX1. Furthermore, in reporter assays we found that TLE1 failed to repress the expression of a RUNX1 target, M-CSFR promoter, when co-transfected with the mutated RUNX1, which is contrary to what has been seen with wildtype RUNX1. Consistent with increased binding between the mutated RUNX1 and CBFβ in the FRET assay, co-transfecting mutant RUNX1 and CBFβ resulted in a significant increase of M-CSFR promoter expression as compared to wildtype RUNX1 with CBFβ. For another RUNX1 target, Hmga2, wildtype RUNX1 and CBFβ decreased Hmga2 expression, which could be restored by adding TLE1. Transfected mutant RUNX1 and CBFβ also decreased Hmga2 expression, but TLE1 could not restore Hmga2 expression when co-transfected with the mutant RUNX1. These findings suggest that the VWRPY-disrupting L472fsX mutation leads to the loss of binding between mutant RUNX1 and TLE1, which in turn resulted in defective repression of the RUNX1 activity by TLE1. To assess for hematopoietic defects in the FPDMM patients with the L472fsX mutation, blood cells from two family members were reprogrammed to induced pluripotent stem cells (iPSCs). Similar to previous studies, iPSCs from these patients gave rise to fewer megakaryocyte progenitors and mature megakaryocytes during in vitro differentiation. In addition, these FPDMM iPSCs showed decrease in hematopoietic stem cell (HSCs) maturation and differentiation to progenitors. The L472fsX mutation in the iPSCs was then corrected by genome editing using zinc finger nuclease. Importantly, the hematopoietic defects of the FPDMM iPSCs mentioned above were rescued after mutation correction. Overall, the findings in these iPSCs differentiation assays showed that the VWRPY motif is essential for RUNX1 activity in megakaryocytes differentiation. In addition, the VWRPY motif is important for HSCs maturation and differentiation to progenitors. To evaluate the impact of this VWRPY-deletion mutation on hematopoiesis in an in vivo model, CRISPR-mediated genome editing was used to generate mice with frameshift mutations that remove the VWRPY domain. Preliminary observations showed that the mutant mice have minor defects in the peripheral blood. More data on this mouse model will be presented at the meeting. In conclusion, we present a novel RUNX1 mutation (L472fsX) with unique hematopoietic defect that has not been reported previously in FPDMM. Our findings imply the significance of the VWRPY motif in megakaryopoiesis, as well as HSCs maturation and differentiation. Disclosures No relevant conflicts of interest to declare.
30
Merriman, Harold L., Andre J. van Wijnen, Scott Hiebert, Joseph P. Bidwell, Edward Fey, Jane Lian, Janet Stein i Gary S. Stein. "The Tissue-Specific Nuclear Matrix Protein, NMP-2, Is a Member of the AML/PEBP2/Runt Domain Transcription Factor Family: Interactions with the Osteocalcin Gene Promoter". Biochemistry 34, nr 40 (październik 1995): 13125–32. http://dx.doi.org/10.1021/bi00040a025.
Pełny tekst źródła
31
Coffman, James A., Carmen V. Kirchhamer, Michael G. Harrington i Eric H. Davidson. "SpRunt-1, a New Member of the Runt Domain Family of Transcription Factors, Is a Positive Regulator of the Aboral Ectoderm-SpecificCyIIIAGene in Sea Urchin Embryos". Developmental Biology 174, nr 1 (luty 1996): 43–54. http://dx.doi.org/10.1006/dbio.1996.0050.
Pełny tekst źródła
32
Huang, Hui, Zachary Waldon, Gordon Chan, Helen Zhu, Hanno Steen, Gen-Sheng Feng, Benjamin Neel i Alan Cantor. "Tyrosine Phosphorylation of Runx1 In Megakaryocytes by Src Family Kinases". Blood 116, nr 21 (19.11.2010): 742. http://dx.doi.org/10.1182/blood.v116.21.742.742.
Pełny tekst źródłaStreszczenie:
Abstract Abstract 742 Runx1 and its cofactor, CBF-beta, are the most frequent targets of chromosomal translocations in human leukemias. Point mutations in Runx-1 also occur in some cases of myelodysplastic syndrome and undifferentiated leukemia. During normal hematopoiesis, Runx1 is required for the ontogeny of all definitive hematopoietic stem cells and for the proper maturation of megakaryocytes (Mks) and lymphocytes. Despite these critical roles, the regulation of Runx1 activity via cell signaling pathways remains incompletely understood. Here, we report that Runx-1 is tyrosine phosphorylated in Mks. This occurs on multiple residues and is mediated by src-family tyrosine kinases (SFKs). Loss of Runx1 tyrosine phosphorylation correlates with phorbol ester induced differentiation of L8057 megakaryoblastic cells, suggesting a negative regulatory function. Consistent with this model, retroviral expression of a tyrosine non-phosphorylatable mutant Runx1 molecule increases primary murine fetal liver Mk maturation and Runx1 target gene expression to a greater extent than wild type Runx1. Moreover, treatment of wild type primary Mks with SFK inhibitors markedly enhances Mk maturation, as previously reported (Lannutti BJ, et al 2005 Blood;105:3875-3878). Treatment of L8057 cells with the pan-tyrosine phosphatase inhibitor Na3VO4, significantly increases Runx1 tyrosine phosphorylation levels, suggesting that tyrosine phosphorylation of Runx1 is dynamically regulated under steady-state conditions. Using a proteomic approach, we found that Runx1 physically interacts with the non-receptor tyrosine phosphatase SHP-2 (Ptpn11). We validated this interaction and showed that it occurs via direct interactions involving the Runx1 runt domain. ShRNA mediated knock down of SHP-2 in L8057 cells increases Runx1 tyrosine phosphorylation levels. Conditional knockout of SHP-2 in Mks using SHP-2fl/fl, PF4-Cre mice leads to reduced peripheral blood platelet counts and delayed platelet recovery following transient anti-GPIb antibody induced immune thrombocytopenia. Lastly, we show that treatment of TPA-induced L8057 cells with Na3VO4 markedly diminishes binding between Runx1 and the key Mk transcription factor GATA-1. Taken together, our data suggest that tyrosine phosphorylation of Runx1 via SFKs inhibits Runx1 function. Dephosphorylation, at least in part via SHP-2, relieves this inhibition and promotes Mk maturation. These effects are likely mediated through altered protein-protein interactions. Disclosures: No relevant conflicts of interest to declare.
33
Hazourli, Sawcene, Pierre Chagnon, Raouf Fetni, Lambert Busque i Josee Hebert. "Overexpression of MEL1 as a Novel Fusion Partner of AML1 in the Blastic Phase of Chronic Myeloid Leukemia with the Recurrent Cryptic Translocation t(1;21)(p36.3;q22)." Blood 106, nr 11 (16.11.2005): 4332. http://dx.doi.org/10.1182/blood.v106.11.4332.4332.
Pełny tekst źródłaStreszczenie:
Abstract Located at 1p36.3, MEL1 is a member of the MDS1/EVI1 gene family and encodes a zinc finger protein with a N-terminal PR-domain. It has been proposed that the overexpression of a modified version of MEL1 lacking the PR domain is oncogenic, whereas MEL1 retaining the PR domain is anti-tumorigenic. MEL1 is known to be overexpressed in some myeloid malignancies with reciprocal translocation t(1;3)(p36.3;q21) characterized by trilineage dysplasia and poor prognosis. It is suggested that the translocation of RPN1 gene at 3q21 in the vicinity of MEL1 gene might activate MEL1 expression through an enhancer element. Here we characterized a recurrent cryptic translocation t(1;21)(p36.3;q22) that fuses MEL1 to AML1 gene in a blastic transformation of chronic myeloid leukemia (CML). Fluorescence in situ hybridization (FISH) analysis with BAC/PAC clones revealed that the breakpoints are in intron 1 of MEL1 and between intron 1 and exon 8 of AML1. RT-PCR analysis showed that AML1-MEL1, but not the reciprocal MEL1-AML1 was expressed. Many splicing variants are present, and all fusions splice the 5′ end of AML1 that contains the RUNT domain with almost the entire MEL1. Furthermore two fusion transcripts contained open reading frames making possible the translation of two forms of AML1-MEL1 fusion proteins. To investigate if AML1-MEL1 leads to an inappropriate expression of MEL1 we performed a quantitative RT-PCR with primers outside and within the fused MEL1 allowing the detection of the normal and the rearranged allele respectively. Interestingly, our data show that while no normal MEL1 transcript was detected, there was an overexpression of the fused MEL1. These results suggest that similarly to AML1-EVI1 gene, overexpression of MEL1 could be regulated by the AML1 promoter in leukemic cells with the AML1-MEL1 fusion gene and might also play an important role in the progression of CML. Moreover, in contrast to previous studies showing an antioncogenic role for the PR domain, our findings indicate that in some leukemias, the overexpression of MEL1 is not restricted to the MEL1 PR-lacking form. This suggests that the mechanism by which the PR domain has his effect, is more complex than previously thought.
34
Kanto, Satoru, Marcin Grynberg, Yoshiyuki Kaneko, Jun Fujita i Masanobu Satake. "A variant of Runx2 that differs from the bone isoform in its splicing is expressed in spermatogenic cells". PeerJ 4 (4.04.2016): e1862. http://dx.doi.org/10.7717/peerj.1862.
Pełny tekst źródłaStreszczenie:
Background.Members of theRunxgene family encode transcription factors that bind to DNA in a sequence-specific manner. Among the three Runx proteins, Runx2 comprises 607 amino acid (aa) residues, is expressed in bone, and plays crucial roles in osteoblast differentiation and bone development. We examined whether theRunx2gene is also expressed in testes.Methods.Murine testes from 1-, 2-, 3-, 4-, and 10-week-old male mice of the C57BL/6J strain andW∕Wvstrain were used throughout the study. Northern Blot Analyses were performed using extracts form the murine testes. Sequencing of cDNA clones and 5′-rapid amplification of cDNA ends were performed to determine the full length of the transcripts, which revealed that the testicular Runx2 comprises 106 aa residues coding novel protein. Generating an antiserum using the amino-terminal 15 aa of Runx2 (Met1to Gly15) as an antigen, immunoblot analyses were performed to detect the predicted polypeptide of 106 aa residues with the initiating Met1. With the affinity-purified anti-Runx2 antibody, immunohistochemical analyses were performed to elucidate the localization of the protein. Furthermore, bioinformatic analyses were performed to predict the function of the protein.Results.ARunx2transcript was detected in testes and was specifically expressed in germ cells. Determination of the transcript structure indicated that the testicularRunx2is a splice isoform. The predicted testicular Runx2 polypeptide is composed of only 106 aa residues, lacks a Runt domain, and appears to be a basic protein with a predominantly alpha-helical conformation. Immunoblot analyses with an anti-Runx2 antibody revealed that Met1in the deduced open reading frame ofRunx2is used as the initiation codon to express an 11 kDa protein. Furthermore, immunohistochemical analyses revealed that the Runx2 polypeptide was located in the nuclei, and was detected in spermatocytes at the stages of late pachytene, diplotene and second meiotic cells as well as in round spermatids. Bioinformatic analyses suggested that the testicular Runx2 is a histone-like protein.Discussion.A variant ofRunx2that differs from the bone isoform in its splicing is expressed in pachytene spermatocytes and round spermatids in testes, and encodes a histone-like, nuclear protein of 106 aa residues. Considering its nuclear localization and differentiation stage-dependent expression, Runx2 may function as a chromatin-remodeling factor during spermatogenesis. We thus conclude that a singleRunx2gene can encode two different types of nuclear proteins, a previously defined transcription factor in bone and cartilage and a short testicular variant that lacks a Runt domain.
35
Paredes, Roberto, Gloria Arriagada, Fernando Cruzat, Alejandro Villagra, Juan Olate, Kaleem Zaidi, Andre van Wijnen i in. "Bone-Specific Transcription Factor Runx2 Interacts with the 1α,25-Dihydroxyvitamin D3 Receptor To Up-Regulate Rat Osteocalcin Gene Expression in Osteoblastic Cells". Molecular and Cellular Biology 24, nr 20 (15.10.2004): 8847–61. http://dx.doi.org/10.1128/mcb.24.20.8847-8861.2004.
Pełny tekst źródłaStreszczenie:
ABSTRACT Bone-specific transcription of the osteocalcin (OC) gene is regulated principally by the Runx2 transcription factor and is further stimulated in response to 1α,25-dihydroxyvitamin D3 via its specific receptor (VDR). The rat OC gene promoter contains three recognition sites for Runx2 (sites A, B, and C). Mutation of sites A and B, which flank the 1α,25-dihydroxyvitamin D3-responsive element (VDRE), abolishes 1α,25-dihydroxyvitamin D3-dependent enhancement of OC transcription, indicating a tight functional relationship between the VDR and Runx2 factors. In contrast to most of the members of the nuclear receptor family, VDR possesses a very short N-terminal A/B domain, which has led to the suggestion that its N-terminal region does not contribute to transcriptional enhancement. Here, we have combined transient-overexpression, coimmunoprecipitation, in situ colocalization, chromatin immunoprecipitation, and glutathione S-transferase pull-down analyses to demonstrate that in osteoblastic cells expressing OC, VDR interacts directly with Runx2 bound to site B, which is located immediately adjacent to the VDRE. This interaction contributes significantly to 1α,25-dihydroxyvitamin D3-dependent enhancement of the OC promoter and requires a region located C terminal to the runt homology DNA binding domain of Runx2 and the N-terminal region of VDR. Together, our results indicate that Runx2 plays a key role in the 1α,25-dihydroxyvitamin D3-dependent stimulation of the OC promoter in osteoblastic cells by further stabilizing the interaction of the VDR with the VDRE. These studies demonstrate a novel mechanism for combinatorial control of bone tissue-specific gene expression. This mechanism involves the intersection of two major pathways: Runx2, a “master” transcriptional regulator of osteoblast differentiation, and 1α,25-dihydroxyvitamin D3, a hormone that promotes expression of genes associated with these terminally differentiated bone cells.
36
Skokowa, Julia, Doris Steinemann, Jenny Katsman-Kuipers, Cornelia Zeidler, Olga Klimenkova, Maksim Klimiankou, Murat Uenalan i in. "Cooperativity Of RUNX1 and CSF3R Mutations In The Development Of Leukemia In Severe Congenital Neutropenia: A Unique Pathway In Myeloid Leukemogenesis". Blood 122, nr 21 (15.11.2013): 444. http://dx.doi.org/10.1182/blood.v122.21.444.444.
Pełny tekst źródłaStreszczenie:
Congenital neutropenia (CN) is a rare inherited disorder of hematopoiesis with a 20% risk of evolving into acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Using next-generation sequencing in 31 CN patients who developed leukemia we found that 20 of the 31 patients (64.5%) had mutations in RUNX1 (runt-related transcription factor 1). Of these 20 patients, 19 had inherited mutations associated with CN. Intriguingly, the majority of patients with RUNX1 mutations (80.5%) also had acquired CSF3R (colony stimulating factor 3 receptor) mutations. Other leukemia-associated mutations (EP300, FLT3-ITD, CBL, and SUZ12) were less frequent. In eight patients, we detected two distinct heterozygous RUNX1 mutations. These mutations were localized to the splice-acceptor site of intron 4, affecting splicing of exons 3 and 4, which encode the Runt homology/DNA binding domain (RHD) of RUNX1, or solely in the RHD or were present in both RHD and trans-activation domain (TAD). In two patients, we were able to perform allele-specific analysis of RUNX1 mutations. Patient #10 had an Phe13TrpfsX14 deletion on one allele of RUNX1 and an Arg139ProfsX47 deletion on the other allele. In Patient #14, two RUNX1 mutations were on the same allele; one of the mutations (Met240Ile) was inherited from the mother and was localized two amino acids before the TAD, and the second acquired mutation (Arg139Gly) was in the RHD of RUNX1. Ten patients with RUNX1 mutations developed monosomy 7 and six patients developed trisomy 21 at diagnosis of leukemia. In contrast to their high frequency in CN evolving into AML, RUNX1 mutations were found in only 9 of 307 (2.9%) patients with de novo pediatric AML. RUNX1 mutations were mainly found in pediatric AML patients with an adverse prognosis. A sequential analysis at stages prior to overt leukemia in ten CN/AML patients showed that RUNX1 mutation is a late event in leukemogenic transformation. In 6 of 10 patients, a CSF3R mutation occurred prior to RUNX1 mutations (24-192 months prior to CN/AML for CSF3R mutations vs. 1-36 months prior to CN/AML for RUNX1 mutations). Interestingly, monosomy 7 or trisomy 21 appeared after acquisition of RUNX1 mutations and no additional chromosomal aberrations were detected by array-CGH. Single-cell analyses in two patients revealed that RUNX1 and CSF3R mutations were segregated in the same malignant clone. Moreover, functional studies demonstrated elevated G-CSF-induced proliferation with diminished myeloid differentiation of hematopoietic CD34+ cells after co-transduction with mutated RUNX1 and CSF3R, in comparison to cells transduced with mutated RUNX1 or mutated CSF3R only. The importance of RUNX1 mutations in leukemogenic transformation was substantially strengthened by the analysis of a unique family with two siblings suffering from CN that subsequently transformed to AML. In both children, cooperating RUNX1 and CSF3Rmutations were detected that were not present in healthy family members. Taken together, the high frequency and the time course of cooperating RUNX1 and CSF3R mutations in CN patients who developed leukemia suggests a unique molecular pathway of leukemogenesis similar as has been reported in the Gilliland-Griffin two-hit hypothesis for AML development. The concomitant detection of RUNX1 and CSF3Rmutations represents a useful biomarker for identifying CN patients with a high risk of progressing to leukemia or MDS. Disclosures: Schnittger: MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Kohlmann:MLL Munich Leukemia Laboratory: Employment.
37
Churpek, Jane E., Jacqueline S. Garcia, Jozef Madzo, Sarah Jackson, Kenan Onel i Lucy A. Godley. "Molecular Characterization of a Novel 3' Mutation in RUNX1 in a New Pedigree with Familial Platelet Disorder." Blood 114, nr 22 (20.11.2009): 1626. http://dx.doi.org/10.1182/blood.v114.22.1626.1626.
Pełny tekst źródłaStreszczenie:
Abstract Abstract 1626 Poster Board I-652 Introduction Familial Platelet Disorder with Propensity to Acute Myelogenous Leukemia (FPD/AML; OMIM 601399) is a rare disorder with an autosomal dominant inheritance pattern characterized by varying degrees of thrombocytopenia, clinical bleeding due to platelet dysfunction, and an increased risk of developing myeloid malignancy. To date, twenty-six families with this disorder have been described and all carry germline RUNX1 mutations as the causative genetic abnormality. The spectrum of RUNX1 mutations includes point mutations within the RUNT domain and frameshift and termination mutations throughout the body of the gene. Here we report identification of a new family with FPD with a novel nonsense mutation resulting in premature protein termination at amino acid 388. Patients and Methods Our four generation pedigree includes a mother (II:4) diagnosed with dysplasia and normal karyotype acute myeloid leukemia now in remission after a matched sibling allogeneic stem cell transplant, and her daughter (III:2) with thrombocytopenia since childhood, excessive bleeding with childbirth, and 5q- syndrome diagnosed at 37 years old. Genomic DNA was obtained from all available family members, and RUNX1 cDNA (transcription variants a through c) was sequenced. In addition, RUNX1 cDNA was analyzed for second mutations in bone marrow samples from both patients at the time of diagnosis of their initial bone marrow malignancy. Results RUNX1 sequencing of germline DNA revealed heterozygosity for a novel nonsense mutation in exon 8 (c.1163C>A), which is predicted to result in premature protein truncation (p.Ser388X). Full sequencing of RUNX1 cDNA from II:4's AML does not show any secondary mutations. Our current efforts include full sequencing of RUNX1 cDNA from III:2's bone marrow malignancy as well as functional studies of the truncated protein. Conclusions We have identified a novel 3' RUNX1 mutation within exon 8, which is predicted to result in premature protein truncation at amino acid 388. To date, this is the most distal mutation identified in an FPD/AML pedigree. The identification of this mutation suggests that the last 100 amino acids, which are known to contain the RUNX1 inhibition domain, contribute an essential function. Further characterization of this RUNX1 mutation and its encoded truncated protein may yield insight into RUNX1's role in leukemogenesis in FPD and de novo AML. Disclosures No relevant conflicts of interest to declare.
38
Takazawa, Y., K. Tsuji, A. Nifuji, H. Kurosawa, Y. Ito i M. Noda. "An osteogenesis-related transcription factor, core-binding factor A1, is constitutively expressed in the chondrocytic cell line TC6, and its expression is upregulated by bone morphogenetic protein-2". Journal of Endocrinology 165, nr 3 (1.06.2000): 579–86. http://dx.doi.org/10.1677/joe.0.1650579.
Pełny tekst źródłaStreszczenie:
Core-binding factor A1 (Cbfa1), also called Pebp2 alpha A/AML3, is a transcription factor that belongs to the runt-domain gene family. Cbfa1-deficient mice are completely incapable of both endochondral and intramembranous bone formation, indicating that Cbfa1 is indispensable for osteogenesis. Maturation of chondrocytes in these mice is also disorganized, suggesting that Cbfa1 may also play a role in chondrogenesis. The aim of this study was to examine the expression and regulation of Pebp2 alpha A/AML3/Cbfa1 expression in the chondrocyte-like cell line, TC6. Northern blot analysis indicated that Cbfa1 mRNA was constitutively expressed as a 6.3 kb message in TC6 cells and the level of Cbfa1 expression was enhanced by treatment with bone morphogenetic protein-2 (BMP2) in a time- and dose-dependent manner. This effect was blocked by an RNA polymerase inhibitor, 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole, but not by a protein synthesis inhibitor, cycloheximide. Western blot analysis of the cell lysates using polyclonal antibody raised against Cbfa1 indicated that BMP2 treatment increased the Cbfa1 protein level in TC6 cells. In TC6 cells, BMP2 treatment enhanced expression of alkaline phosphatase and type I collagen mRNAs but suppressed that of type II collagen mRNA. In addition to TC6 cells, Cbfa1 mRNA was also expressed in primary cultures of chondrocytes and BMP2 treatment enhanced Cbfa1 mRNA expression in these cells similarly to its effect on TC6 cells. These data indicate that the Pebp2 alpha A/AML3/Cbfa1 gene is expressed in a chondrocyte-like cell line, TC6, and its expression is enhanced by treatment with BMP.
39
Mao, Shifeng, Richard C. Frank, Jin Zhang, Yasushi Miyazaki i Stephen D. Nimer. "Functional and Physical Interactions between AML1 Proteins and an ETS Protein, MEF: Implications for the Pathogenesis of t(8;21)-Positive Leukemias". Molecular and Cellular Biology 19, nr 5 (1.05.1999): 3635–44. http://dx.doi.org/10.1128/mcb.19.5.3635.
Pełny tekst źródłaStreszczenie:
ABSTRACT The AML1 and ETS families of transcription factors play critical roles in hematopoiesis; AML1, and its non-DNA-binding heterodimer partner CBFβ, are essential for the development of definitive hematopoiesis in mice, whereas the absence of certain ETS proteins creates specific defects in lymphopoiesis or myelopoiesis. The promoter activities of numerous genes expressed in hematopoietic cells are regulated by AML1 proteins or ETS proteins. MEF (for myeloid ELF-1-like factor) is a recently cloned ETS family member that, like AML1B, can strongly transactivate several of these promoters, which led us to examine whether MEF functionally or physically interacts with AML1 proteins. In this study, we demonstrate direct interactions between MEF and AML1 proteins, including the AML1/ETO fusion protein, in t(8;21)-positive acute myeloid leukemia (AML) cells. Using mutational analysis, we identified a novel ETS-interacting subdomain (EID) in the C-terminal portion of the Runt homology domain (RHD) in AML1 proteins and determined that the N-terminal region of MEF was responsible for its interaction with AML1. MEF and AML1B synergistically transactivated an interleukin 3 promoter reporter gene construct, yet the activating activity of MEF was abolished when MEF was coexpressed with AML1/ETO. The repression by AML1/ETO was independent of DNA binding but depended on its ability to interact with MEF, suggesting that AML1/ETO can repress genes not normally regulated by AML1 via protein-protein interactions. Interference with MEF function by AML1/ETO may lead to dysregulation of genes important for myeloid differentiation, thereby contributing to the pathogenesis of t(8;21) AML.
40
Garcia, Jacqueline S., Jozef Madzo, Devin Cooper, Sarah A. Jackson, Kenan Onel, Richard A. Larson, Andrew Artz i Lucy A. Godley. "Pre-Donor Evaluation of an HLA Matched Sibling Identifies a Novel Inherited RUNX1 Mutation Encoding a Missense Mutation Found Outside of the RUNT Domain in Familial Platelet Disorder". Blood 116, nr 21 (19.11.2010): 2709. http://dx.doi.org/10.1182/blood.v116.21.2709.2709.
Pełny tekst źródłaStreszczenie:
Abstract Abstract 2709 Introduction: RUNX1 is a critical transcription factor in the regulation of normal hematopoiesis. Inherited RUNX1 mutations have been identified as the culprit genetic lesion in Familial Platelet Disorder (FPD; OMIM 601399), a rare autosomal dominant condition with a propensity to myeloid malignancy. The spectrum of RUNX1 mutations causing the FPD/acute myeloid leukemia (AML) syndrome includes frameshift and termination mutations detected throughout the gene, and missense mutations clustered within the highly conserved RUNT homology domain (RHD), which is responsible for both DNA binding and heterodimerization with CBFβ/PEBP2β, the non-DNA binding regulatory subunit. We present a new FPD/AML pedigree with a novel missense mutation leading to a single amino acid change, L56S. This L56S mutation is the first reported point mutation in this syndrome to be found outside of the RHD. Patients and Methods: Our new pedigree involves a 41-year-old man (proband) diagnosed with myelodysplastic syndrome (MDS, specifically refractory anemia with excess blasts type-2) with a normal karyotype. He was initiated on azacitidine, which was administered on a seven-day treatment schedule every four weeks. Bone marrow biopsy analysis after six monthly cycles of azacitidine showed persistent MDS, with similar findings after a total of ten monthly cycles. Given his lack of a clinical response, his young age and good performance status, he was referred to The University of Chicago for allogeneic hematopoietic stem cell transplantation (HCT). Routine pre-transplant evaluation revealed mild thrombocytopenia (platelets = 123,000 K/μl) in his HLA-matched brother. In addition, his father was reported to have thrombocytopenia. Clinical concern for an inherited condition initiated the investigation for a RUNX1 mutation in the family. Results: We sequenced full-length cDNA synthesized from leukocyte-derived RNA collected from the proband's sibling with thrombocytopenia, and detected a novel missense germline mutation in exon 4 at nucleotide position 371, causing a T to C mutation leading to a single amino acid change in the RUNX1 protein, L56S. This amino acid substitution is located N-terminal to the RHD (aa 76–209). RUNX1 sequencing of the proband with MDS demonstrated the same mutation. The RUNX1 RHD and the transactivation domain remain intact in this mutant. Initial transactivation assays using a luciferase reporter assay performed in triplicate demonstrated similar levels of activation as wild-type RUNX1. Corresponding Western blot analysis showed similar levels of protein expression of both wild-type RUNX1 and mutant RUNX1 transfected cell lines using an anti-RUNX1-antibody. Current studies include determination of the transactivation ability of mutant RUNX1 with its heterodimerization partner, CBFβ/PEBP2β, testing the DNA binding ability of this RUNX1 mutant by electrophoretic mobility shift assay, and analysis of the RUNX1 cDNA for an acquired biallelic mutation in leukocytes collected from the proband's bone marrow aspirate at the time of diagnosis of bone marrow malignancy. Conclusions: FPD/AML is likely an underreported condition. Clinical suspicion for this inherited syndrome may be raised by the presence of mild to moderate thrombocytopenia in healthy siblings, and should lead to prompt screening for germline RUNX1 mutations to confirm an inherited predisposition and to prevent siblings carrying RUNX1 mutations from being selected as HCT donors. In vitro studies of identified RUNX1 mutations may elucidate potential mechanisms involved in the pathogenesis of the FPD/AML syndrome. Disclosures: No relevant conflicts of interest to declare.
41
Grossmann, Vera, Alexander Kohlmann, Hans-Ulrich Klein, Sonja Schindela, Susanne Schnittger, Martin Dugas, Wolfgang Kern, Torsten Haferlach i Claudia Haferlach. "Targeted Next-Generation Sequencing and Genome-Wide High-Resolution Copy Number DNA Arrays Allow the Identification of Five Novel RUNX1 Fusions In Hematological Malignancies." Blood 116, nr 21 (19.11.2010): 1193. http://dx.doi.org/10.1182/blood.v116.21.1193.1193.
Pełny tekst źródłaStreszczenie:
Abstract Abstract 1193 RUNX1 is a crucial transcription factor involved in cell lineage differentiation during hematopoiesis. It contains a “Runt homology domain” (RHD; exons 3–5, amino acids 50–177) and a transactivation domain (TAD; exon 8, amino acids 291–371). RUNX1 can act as an activator or repressor of target gene expression and thus far two different mechanisms of somatically acquired alterations have been recognized: intragenic mutations and translocations. Most of the translocations involving RUNX1 lead to the formation of a fusion gene consisting of the 5` part of RUNX1 fused to sequences on partner chromosomes. We here present data on 5 cases, 4 acute myeloid leukemias (AML) and 1 chronic myelomonocytic leukemia (CMML) patient, respectively, where previous cytogenetic and FISH analyses revealed reciprocal translocations involving RUNX1. However, even sophisticated molecular diagnostic work-up failed to identify the corresponding RUNX1 fusion partners. Therefore, we used a combination of 454 shotgun pyrosequencing and long-oligonucleotide sequence capture microarrays to reveal these unknown RUNX1 partner genes in four cases. In detail, we performed DNA sequence enrichment using microarrays containing capture probes that were covering a contiguous region on chr. 21 (36,160,098 – 36,421,641), thereby allowing a specific enrichment by hybridization for genomic DNA where the RUNX1 gene is located (Roche NimbleGen 385K chip, Penzberg, Germany). This targeted next-generation sequencing (NGS) assay enabled to capture and sequence single reads mapping to both RUNX1 and other genomic regions (Burrows-Wheeler Aligner's Smith-Waterman algorithm). In median, 324 bp per patient (170,000 reads) with an 18-fold coverage were sequenced and in all cases chimeric reads were detectable, thereby confirming the presence of RUNX1 translocations and, moreover, identifying and characterizing 4 novel fusions on a molecular level. In one AML case, KCNMA1 was fused to RUNX1. KCNMA1, a potassium large conductance calcium-activated channel family member on chromosome 10q22.3, had recently been described to play a role in breast cancer invasion and metastasis to brain. In our case, as confirmed by RT-PCR and Sanger sequencing, the chimeric RUNX1-KCNMA1 fusion led to the disruption of the RHD of RUNX1. In the three additional cases, RUNX1 was fused to genomic regions on chromosomes 10q22, 17q21, and 5q13.3, respectively. The RUNX1-10q22 and the reciprocal 10q22-RUNX1 fusion were confirmed by PCR from genomic DNA and subsequent Sanger sequencing. According to its genomic structure the translocation RUNX1-chr.10q22 will result into the translation of a truncated RUNX1 protein with an intact RHD, but without TAD. Notably, in the remaining two cases, chr.17q21-RUNX1 and chr.5q13.3-RUNX1, only the reciprocal fusion events were detectable by PCR. In case chr.17q21-RUNX1 the translocation would disrupt RUNX1 after the RHD. In chr.5q13.3-RUNX1 the predicted fusion would not impact the RHD and TAD domains because the breakpoint is located before exon 1. In the fifth patient, we performed an analysis using a high-resolution genome-wide cytogenetic copy number DNA microarray to resolve a novel t(X;21)(p11;q22). In this case, the derivative chromosome × was duplicated, leading to a partial trisomy 21q and a partial trisomy X. On chr. 21 the breakpoint was mapped to be located in intron 6–7 within the RUNX1 gene. The breakpoint on the X-chromosome mapped to Xp11.23, thus leading to a truncated RUNX1 protein without the TAD domain. In summary, RUNX1 rearrangements either led to RUNX1 with an intact RHD and TAD (n=1), RUNX1 with an intact RHD but without TAD (n=3, dominant negative effect; similar to RUNX1-RUNX1T1), or to RUNX1 with a disrupted RHD and without TAD domains, leading to haploinsufficiency (n=1). In conclusion, the RUNX1 recombinome is an interesting target to understand pathogenetic heterogeneity in hematological malignancies. Here, we demonstrated that NGS and copy number DNA microarrays allow the identification of novel RUNX1 fusion partners not detectable by standard molecular techniques and reveals that cytogenetic reciprocal translocations lead to different types of RUNX1 alterations. Disclosures: Grossmann: MLL Munich Leukemia Laboratory: Employment. Kohlmann:MLL Munich Leukemia Laboratory: Employment. Schindela:MLL Munich Leukemia Laboratory: Employment. Schnittger:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership, Research Funding.
42
Kirito, Keita, Toru Mitsumori, Takahiro Nagashima, Masae Kunitama, Kei Nakajima, Kozue Yoshida, Yongzhen Hu, Mitsuhiro Yanagai i Norio Komatsu. "A Novel Inherited Single-Nucleotide Mutation in 5′-UTR in the Transcription Factor RUNX1 in Familial Platelet Disorder with Propensity To Develop Myeloid Malignancies." Blood 108, nr 11 (16.11.2006): 1917. http://dx.doi.org/10.1182/blood.v108.11.1917.1917.
Pełny tekst źródłaStreszczenie:
Abstract RUNX1 transcription factor plays pivotal roles in the development of definitive hematopoiesis. Allelic loss of the gene causes complete absence of fetal liver hematopoiesis. In addition to normal hematopoiesis, aberrant expression of RUNX1 is also involved in the pathogenesis of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Familial platelet disorder with propensity to develop myeloid malignancies (FPD/AML, OMIM 601399) is a rare autosomal dominant disorder characterized by thrombocytopenia, dysfunction of platelets and predisposition to the development of myeloid malignancies. Recent studies revealed that inherited mutation of RUNX1 gene is responsible for the onset of FPD/AML. To date, 12 families of FPD/AML have been reported in the literature, and point mutation in the RUNT domain or loss of heterozygocity (LOH) of the gene has been identified in the pedigree. Here, we report a Japanese family with FPD/AML with a novel mutation of RUNX1 gene. A 38-year-old man was admitted to our hospital because of MDS (RAEB) in August 2003. Cytogenetic analysis revealed abnormal karyotype; 46XY, t (7; 8)(q34; q11). In addition, prolongation of bleeding time and abnormal platelet aggregation were observed. His son and daughter also showed mild bleeding tendency and had mild thrombocytopenia. In April 2006, the daughter developed MDS (RAEB) with trisomy 8 at age 16. After informed consent, blood samples were obtained from all family members and all 9 exons of RUNX1 gene were sequenced. We identified a novel G to T single-nucleotide mutation in the 5′-untranslated region (5′-UTR) in the exon1, corresponding to position 102 of RUNX1 transcripts (NCBI accession no. D43969). This mutation was also found in all the affected individuals but not in the healthy members. To investigate the possibility of hemizygous intragenic deletion of the gene, we performed an array- based comparative genomic hybridization using Affymetrix GeneChip Human Mapping 250K set including 23 SNPs in RUNX1 gene. We found no loss of heterozygosity of RUNX1 gene in the affected members. Because the mutation is located in 5′-UTR, we investigated whether this mutation might affect the expression of RUNX1 transcripts. Transcription of RUNX1 is regulated by two distinct promoter regions, distal and proximal, resulting in the generation of transcripts having different 5′-UTRs. The 5′-UTR of transcripts controlled by distal promoter contains exon1 (distal form), whereas that of transcripts controlled by proximal promoter contains exon3 but not exon1 (proximal form). We analyzed the expression level of both transcripts from bone marrow cells using quantitative RT-PCR. Affected individuals showed 10 to 15 times higher expression of the distal form of RUNX1 transcripts, compared to normal controls (n=3), MDS patients (n=3) and AML patient (n=1). Considering that not only haploinsufficiney but also overexpression of RUNX1 can cause AML, aberrant expression of RUNX1 induced by the point mutation in 5′-UTR may be involved in progression of FPD/AML.
43
Cesari, Stella, John Moore, Chunhong Chen, Daryl Webb, Sambasivam Periyannan, Rohit Mago, Maud Bernoux, Evans S. Lagudah i Peter N. Dodds. "Cytosolic activation of cell death and stem rust resistance by cereal MLA-family CC–NLR proteins". Proceedings of the National Academy of Sciences 113, nr 36 (23.08.2016): 10204–9. http://dx.doi.org/10.1073/pnas.1605483113.
Pełny tekst źródłaStreszczenie:
Plants possess intracellular immune receptors designated “nucleotide-binding domain and leucine-rich repeat” (NLR) proteins that translate pathogen-specific recognition into disease-resistance signaling. The wheat immune receptors Sr33 and Sr50 belong to the class of coiled-coil (CC) NLRs. They confer resistance against a broad spectrum of field isolates of Puccinia graminis f. sp. tritici, including the Ug99 lineage, and are homologs of the barley powdery mildew-resistance protein MLA10. Here, we show that, similarly to MLA10, the Sr33 and Sr50 CC domains are sufficient to induce cell death in Nicotiana benthamiana. Autoactive CC domains and full-length Sr33 and Sr50 proteins self-associate in planta. In contrast, truncated CC domains equivalent in size to an MLA10 fragment for which a crystal structure was previously determined fail to induce cell death and do not self-associate. Mutations in the truncated region also abolish self-association and cell-death signaling. Analysis of Sr33 and Sr50 CC domains fused to YFP and either nuclear localization or nuclear export signals in N. benthamiana showed that cell-death induction occurs in the cytosol. In stable transgenic wheat plants, full-length Sr33 proteins targeted to the cytosol provided rust resistance, whereas nuclear-targeted Sr33 was not functional. These data are consistent with CC-mediated induction of both cell-death signaling and stem rust resistance in the cytosolic compartment, whereas previous research had suggested that MLA10-mediated cell-death and disease resistance signaling occur independently, in the cytosol and nucleus, respectively.
44
Satoh, Yusuke, Itaru Matsumura, Sachiko Ezoe, Hirokazu Tanaka, Takafumi Yokota, Jun Ishikawa, Kenji Oritani i Yuzuru Kanakura. "The Function of AML1 (RUNX1) C-Deletion Mutant in Hematopoietic Stem/Progenitor Cells." Blood 106, nr 11 (16.11.2005): 1738. http://dx.doi.org/10.1182/blood.v106.11.1738.1738.
Pełny tekst źródłaStreszczenie:
Abstract AML1 (RUNX1) is a family member of heterodimeric transcription factors named core binding factors (CBFs). AML1 binds to its target DNA through the RUNT domain and is frequently involved in chromosomal translocations associated with human leukemias. Also, AML1 was found to be mutated in a substantial fraction of myelodysplastic syndrome (MDS) patients. Although most of AML1 mutations identified in AML patients were located in the N-terminal region, the C-terminal mutaions yielding mutant AML lacking the C-terminal domain (AML1dC) were frequently observed in MDS patients. Based on the fact that the haploinsufficiency of AML1, which results from heterozygous missense mutation of the AML1 gene, causes familial platelet disorder (FPD) with predisposition to AML, and that the conditional deletion of the AML1 gene using the Cre-LoxP system in adult mice results in the failure of megakaryopoiesis and subsequent platelet production, we speculate that AML1 might be involved in the thrombopoietin (TPO)/c-Mpl (its receptor) system, which is a major regulator of this process. Also, we examined the mechanism through which AML1dC affects the function of wtAML1. At first, we examined the role of AML1 in the regulation of the c-mpl promoter with luciferase assays. In 293T cells, we found that wild-type AML1 (wtAML1) activated the c-mpl promoter by 3.5 fold. This effect was dose-dependently inhibited by a dominant-negative form of AML1, AML1-MTG8. In addition, we found that AML1dC inhibited the function of wtAML1 with efficiencies similar to AML1-MTG8 (or with lesser efficiencies than AML1-MTG8). Next, we tried to determine the element responsive to AML1 in the c-mpl promoter. Using various mutants of the c-mpl promoter, we found that wtAML1 activates the element between −135 and −116, which contains the typical AML1-binding sequence. Furthermore, we confirmed that wtAML1 bound to this element in electrophoretic mobility shift assays using nuclear extract of 293T cells transfected with wtAML1. Also, in this assay, we found that AML1dC bound to the consensus DNA sequence more strongly than wtAML1 and inhibited the DNA-binding of wtAML1 competitively. Next, we examined the roles of AML1 in the c-Mpl expression in hematopoietic cells by expressing AML1dC in the OP-9 system, in which hematopoietic cells develop from embryonic stem (ES) cells during the coculture with OP-9 cells. In contrast to the results obtained from 293T cells, when AML1dC was inducibly expressed with the Tet-off system, c-Mpl was expressed more intensely in Lin−Sca1+ hematopoietic stem/progenitor cells than mock-transfected Lin−Sca1+ cells, indicating that AML1 is a negative regulator of the c-Mpl expression in hematopoietic stem/progenitor cells. In contrast, the surface expression of c-Mpl in mature megakaryocytes was hardly affected by AMLdC in the OP-9 system. We also examined the effects of AML1 on the c-Mpl expression in normal murine bone marrow Lin−Sca-1+ cells by expressing AML1dC with the retrovirus system. As a result, we again found that AML1dC enhanced the c-Mpl expression in murine Lin−Sca-1+ cells. Together, our results indicate that AML1 regulates the c-Mpl expression both positively and negatively according to cell types (cf, 293T cells, hematopoietic stem/progenitor cells, and megakaroycytes). Particularly, although AML1 was previously reported to positively regulate of the c-Mpl expression in megakaryocytes, it was supposed be a negative regulator in hematopoietic stem/progenitor cells.
45
Brown, Anna L., Christopher N. Hahn, Catherine Carmichael, Ella Wilkins, Milena Babic, Chan-Eng Chong, Xiao-Chun Li i in. "Expanded Phenotypic and Genetic Heterogeneity in the Clinical Spectrum of FPD-AML: Lymphoid Malignancies and Skin Disorders Are Common Features in Carriers of Germline RUNX1 Mutations". Blood 128, nr 22 (2.12.2016): 1212. http://dx.doi.org/10.1182/blood.v128.22.1212.1212.
Pełny tekst źródłaStreszczenie:
Abstract Background: This year, germline predisposition to haematological malignancy (HM) debuts in the World Health Organization classification of myeloid neoplasms and acute leukemia (Blood, 2016;127:2391). It has been 17 years since germline mutations in RUNX1 were found to lead to familial platelet disorder (FPD) with predisposition to myelodysplastic syndrome and acute myeloid leukaemia (MDS/AML) (Nat Genet. 1999;23:166). Now, nearly 80 families have been reported with damaging germline mutations or deletions affecting RUNX1 function, associated with FPD, making it an increasingly significant clinical presence. Although thrombocytopenia and platelet dysfunction are present in almost all RUNX1 mutant carriers, we and others have observed that the predisposition to HM varies between family members, with respect to age at diagnosis and the type of malignancy, and in some cases RUNX1 mutation carriers have no apparent HM development over their lifespan. The reasons for this heterogeneity are currently unknown. Aims: We are conducting an international collaborative study examining RUNX1 mutated families. The aim of the research project is to classify the range of phenotypes correlated with RUNX1 mutations comprehensively (including non-malignant phenotypes such as skin disorders) and to determine if the type of RUNX1 mutation and the presence of other germline and acquired mutations in relevant HM genes correlate with the likelihood of HM development, or the type of HM that develops. Across all of our data we aim to analyse clinically relevant information that will be used to inform prognosis and clinical management in germline RUNX1 mutation carriers. Results:From a review of the literature for previously characterised RUNX1 mutant families most mutations are predicted to be loss-of-function, with the combination of frameshift, stopgain, splicing and deletion accounting for the majority of alterations (57, 70%) compared to missense mutations (22, Figure 1). The most common sites of mutation are R201 and R204, affected by both missense and stopgain (10 total), which lie within the nuclear localisation signal at the end of the RUNT domain (Figure 1). We also surveyed in detail 12 RUNX1 pedigrees with both novel and previously described missense, frameshift, stopgain and deletion mutations and found that, while all families developed myeloid malignancies, 6 families also had individuals who developed lymphoid malignancy (most often Acute lymphoblastic leukemia (ALL)) which was heritable in sub-families, and subject to anticipation (e.g see IV-5 and V-5 in Figure 2). Consistent with population genome wide association studies identifying RUNX1 as a susceptibility locus for psoriasis (J Autoimmun. 2015;64:66), we find that skin conditions (psoriasis, eczema) are common, and present in germline RUNX1 carriers in 50% of our families; most commonly observed in families with stopgain and frameshift mutations. Genomic analysis of selected samples confirms that mutation of the other RUNX1 allele is the most commonly acquired mutation in germline RUNX1 mutation carriers developing HM. Alterations of chromosomes 21 and 7 are also common. DNMT3A and PHF6 acquired mutations were the next most frequently observed in tumors and mutations in U2AF1 and ASXL1 in the blood of RUNX1 carriers without HM were observed, suggestive of pre-HM clonal expansion. Finally, in a family with a novel R169I RUNX1 mutation, a rare germline ASXL1 variant (E1102D, 1.0% in ExAC) was found in two RUNX1 carriers who developed early onset AML. This variant is also significantly enriched in an MDS cohort unselected for family history compared to the general population (HR 1.3, p=0.02), as well as ASXL1 N986S (0.1% in ExAC, HR 3.3, p=0.0002) suggesting they operate as germline HM risk modifiers. Interestingly RUNX1 and ASXL1 acquired mutations often co-occur in sporadic MDS/AML and our data suggests this collaboration may also occur at the germline level. Conclusions:Annotation of skin phenotypes co-existent with a family history of haematological malignancy may assist in identifying RUNX1 mutant families. Both acquired and germline mutations in known HM genes may modify germline RUNX1 driven HM penetrance and phenotype. Our data suggest that screening of RUNX1 germline mutation carriers for germline and acquired variants in other HM genes could provide an important tool for defining risk and requires further investigation. Disclosures Owen: Pharmacyclics: Research Funding; Janssen: Honoraria; Roche: Honoraria, Research Funding; Novartis: Honoraria; Gilead: Honoraria, Research Funding; Lundbeck: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Abbvie: Honoraria. Godley:UpToDate: Honoraria; Onconova, Inc.: Research Funding.
46
Sun, Qing, Nicholas C. Collins, Michael Ayliffe, Shavannor M. Smith, Jeff Drake, Tony Pryor i Scot H. Hulbert. "Recombination Between Paralogues at the rp1 Rust Resistance Locus in Maize". Genetics 158, nr 1 (1.05.2001): 423–38. http://dx.doi.org/10.1093/genetics/158.1.423.
Pełny tekst źródłaStreszczenie:
Abstract Rp1 is a complex rust resistance locus of maize. The HRp1-D haplotype is composed of Rp1-D and eight paralogues, seven of which also code for predicted nucleotide binding site-leucine rich repeat (NBS-LRR) proteins similar to the Rp1-D gene. The paralogues are polymorphic (DNA identities 91-97%), especially in the C-terminal LRR domain. The remaining family member encodes a truncated protein that has no LRR domain. Seven of the nine family members, including the truncated gene, are transcribed. Sequence comparisons between paralogues provide evidence for past recombination events between paralogues and diversifying selection, particularly in the C-terminal half of the LRR domain. Variants selected for complete or partial loss of Rp1-D resistance can be explained by unequal crossing over that occurred mostly within coding regions. The Rp1-D gene is altered or lost in all variants, the recombination breakpoints occur throughout the genes, and most recombinant events (9/14 examined) involved the same untranscribed paralogue with the Rp1-D gene. One recombinant with a complete LRR from Rp1-D, but the aminoterminal portion from another homologue, conferred the Rp1-D specificity but with a reduced level of resistance.
47
Yu, Kai, Matthew Merguerian, Natalie Deuitch, Erica Bresciani, Joie Davis, Kathleen Craft, Lea C. Cunningham i Paul P. Liu. "Genomic Landscape of RUNX1-Familial Platelet Disorder with Myeloid Malignancies Reveals Rising Clonal Hematopoiesis". Blood 138, Supplement 1 (5.11.2021): 1090. http://dx.doi.org/10.1182/blood-2021-151781.
Pełny tekst źródłaStreszczenie:
Abstract Familial platelet disorder with associated myeloid malignancies (FPDMM) is a rare autosomal dominant disease caused by germline RUNX1 mutations. FPDMM patients have defective megakaryocytic development, low platelet counts, prolonged bleeding times, and a life-long risk (20-50%) of developing hematological malignancies. FPDMM is a rare genetic disease in need of comprehensive clinical and genomic studies. In early 2019 we launched a longitudinal natural history study of patients with FPDMM at the NIH Clinical Center and by May 2021 we have enrolled 98 patients and 100 family controls from 55 unrelated families. Genomic data have been generated from 56 patients in 24 families, including whole exome sequencing (WES), RNA-seq, and single-nucleotide polymorphism (SNP) array. We have identified 21 different germline RUNX1 variants among these 24 families, which include lost-of-function mutations throughout the RUNX1 gene, but pathogenic/likely pathogenic missense mutations are mostly clustered in the runt-homology domain (RHD). As an important form of RUNX1 germline mutations, five splice site variants located between exon 4-5 and exon 5-6 were identified in 6 families, which led to the productions of novel transcript forms that are predicted to generate truncated RUNX1 proteins. Large deletions affecting the RUNX1 gene are also common, ranging from 50 Kb to 1.5Mb, which were detected in 8 of the 55 enrolled families. Besides RUNX1, copy number variation (CNV) analysis from both SNP array and WES showed limited CNV events in non-malignant FPDMM patients. In addition, fusion gene analysis did not detect any in-frame fusion gene in these patients, indicating a relatively stable chromosome status in FPDMM patients. Somatic mutation landscape shows that the overall mutation burden in non-malignant FPDMM patients is lower than AML or other cancer types. However, in 13 of the 44 non-malignant patients (30%), somatic mutations were detected in at least one of the reported clonal hematopoiesis of indeterminate potential (CHIP) genes, significantly higher than the general population (4.3%). Moreover, 85% of our patients who carried CHIP mutations are under 65 years of age; in the general population, only 10% of people above 65 years of age and 1% of people under 50 were reported to carry CHIP mutations. Among mutated genes related to clonal hematopoiesis, BCOR is the most frequently mutated gene (5/44) in our FPDMM cohort, which is not a common CHIP gene among the general population. Mutations in known CHIP genes including SF3B1, TET2, and DNMT3A were also found in more than one patient. In addition, sequencing of 5 patients who already developed myeloid malignancies detected somatic mutations in BCOR, TET2, NRAS, KRAS, CTCF, KMT2D, PHF6, and SUZ12. Besides reported CHIP genes or leukemia driver genes, 3 unrelated patients carried somatic mutations in the NFE2 gene, which is essential for regulating erythroid and megakaryocytic maturation and differentiation. Two of the NFE2 mutations are nonsense mutations, and the other is a missense mutation in the important functional domain. NFE2 somatic mutations may play important roles in developing malignancy because 2 of the 3 patients already developed myeloid malignancies. For multiple patients in our cohort, we have sequenced their DNA on multiple timepoints. We have observed patients with expanding clones carrying FKBP8, BCOR or FOXP1 mutations. We have also observed a patient with relatively stable clone(s) with somatic BCOR, DNMT3A, and RUNX1T1, who have been sampled over more than four years. We will follow these somatic mutations through sequencing longitudinally and correlate the findings with clinical observations to see if the dynamic changes of CHIP clones harboring the mutations give rise to MDS or leukemia. In summary, the genomic analysis of our new natural history study demonstrated diverse types of germline RUNX1 mutations and high frequency of somatic mutations related to clonal hematopoiesis in FPDMM patients. These findings indicate that monitoring the dynamic changes of these CHIP mutations prospectively will benefit patients' clinical management and help us understand possible mechanisms for the progression from FPDMM to myeloid malignancies. Disclosures No relevant conflicts of interest to declare.
48
Kwan, Tsz-Ki, Chi-Keung Cheng, Suk-Hang Cheng, Natalie P. H. Chan, Rosalina Ip, Raymond S. M. Wong, Sze-Fai Yip, Chi-Kong Li i Margaret H. L. Ng. "RUNX3 Expression Is an Independent Prognostic Factor in Cytogenetically Abnormal Adult Acute Myeloid Leukemia (AML) Patients with Wild-Type FLT3." Blood 116, nr 21 (19.11.2010): 1662. http://dx.doi.org/10.1182/blood.v116.21.1662.1662.
Pełny tekst źródłaStreszczenie:
Abstract Abstract 1662 RUNX3 is a member of Runt-related domain (RUNX) transcription factor family, which regulates cell proliferation and differentiation. Recent studies have suggested a role of RUNX3 in hematopoiesis. Our group previously showed that RUNX3 expression was repressed by fusion protein RUNX1-ETO and CBFβ-MYH11 in core-binding factor acute myeloid leukemia (CBF-AML) and had prognostic implication in childhood AML patients (Cheng et al, 2008). However, the prognostic value of RUNX3 in adult AML remains hitherto unaddressed. To investigate the prognostic value of RUNX3 expression in adult AML patients, we measured RUNX3 mRNA levels in the diagnostic bone marrow samples from 60 adult patients with de novo AML by real time quantitative PCR (RQ-PCR). Mutation status of KIT, FMS-like tyrosine kinase 3 (FLT3), nucleophosmin (NPM1) and CCAAT/enhancer-binding protein α (CEBPA) were assessed by direct sequencing. The adult AML patients (n=60) were dichotomized at median RUNX3 level and divided into high and low expression groups. There was no significant difference in age, sex, white blood cell (WBC) count, frequency of KIT, FLT3, NPM1 and CEBPA mutations between the two groups. Concordant with our previous observation, the low RUNX3 expression group was significantly associated with CBF-AML characterized by t(8;21) and inv(16) (p=0.002). However, in contrast to our previous findings in childhood AML, we observed significant association of survival with RUNX3 levels only when patients were stratified according to their cytogenetics and FLT3 mutation status but not when the whole patient cohort was analyzed or when the patients were stratified by age, sex, WBC count or other genetic aberrations (KIT, NPM1 or CEBPA mutation). In each cytogenetically normal and abnormal subgroup, AML patients were dichotomized at median RUNX3 into high and low expression groups. Among adult AML patients with abnormal karyotypes (n=36), high RUNX3 expression tended to have worse event-free survival (EFS) (high vs low= 50% vs 67%, p=0.213) and overall survival (OS) (61% vs 78%, p=0.233). Because potential relationship between FLT3 mutation status and RUNX3 expression was suggested in the study by Lacayo et al (2004), analysis was performed with further stratification according to the FLT3 status. Among cytogenetically abnormal patients with wild-type FLT3, high RUNX3 expression was significantly associated with poorer OS (53% vs 80%, p=0.048) and tended to have worse EFS (53% vs 73%, p=0.077). In multivariate analysis, RUNX3 expression was an independent prognostic factor for both EFS (p=0.026) and OS (p=0.021) along with age (p=0.013 and 0.004 respectively) and WBC count (p<0.0005 and 0.001 respectively) in this patient subgroup. The group of patients with mutant FLT3 was too small for analysis. In contrast to the finding in cytogenetically abnormal patients, there was a trend towards poorer EFS (high vs low = 50% vs 20%, p=0.066) and OS (50% vs 30%, p=0.118) for low RUNX3 expression in adult AML patients with a normal karyotype (n=20). However, no significant association was observed after stratification with FLT3 status. In conclusion, our findings suggested that unlike in childhood AML patients, the prognostic impact of RUNX3 in adult AML patients was dependent on cytogenetic status and that high RUNX3 expression was an independent adverse prognostic factor in cytogenetically abnormal adult AML patients with wild-type FLT3. A larger prospective study is currently underway to confirm the prognostic value of RUNX3 in adult AML. Disclosures: No relevant conflicts of interest to declare.
49
Howles, Paul, Greg Lawrence, Jean Finnegan, Helen McFadden, Michael Ayliffe, Peter Dodds i Jeff Ellis. "Autoactive Alleles of the Flax L6 Rust Resistance Gene Induce Non-Race-Specific Rust Resistance Associated with the Hypersensitive Response". Molecular Plant-Microbe Interactions® 18, nr 6 (czerwiec 2005): 570–82. http://dx.doi.org/10.1094/mpmi-18-0570.
Pełny tekst źródłaStreszczenie:
L6 is a nucleotide binding site-leucine rich repeat (NBS-LRR) gene that confers race-specific resistance in flax (Linum usitatissimum) to strains of flax rust (Melampsora lini) that carry avirulence alleles of the AvrL567 gene but not to rust strains that carry only the virulence allele. Several mutant and recombinant forms of L6 were made that altered either the methionine-histidine-aspartate (MHD) motif conserved in the NBS domain of resistance proteins or exchanged the short domain C-terminal to the LRR region that is highly variable among L allele products. In transgenic flax some of these alleles are autoactive; they cause a gene dosage-dependent dwarf phenotype and constitutive expression of genes that are markers for the plant defense response. Their effects and penetrance ranged from extreme to mild in their degree of plant stunting, survival, and reproduction. Dwarf plants were also resistant to flax rust strains virulent to wild-type L6 plants, and this nonspecific resistance was associated with a hypersensitive response (HR) at the site of rust infection. The strongest autoactive allele, expressed in Arabidopsis from an ethanol-inducible promoter, gave rise to plant death dependent on the enhanced disease susceptibility 1 (EDS1) gene, which indicates that the mutant flax (Linaceae) L6 gene can signal cell death through a defined disease-resistance pathway in a different plant family (Brassicaceae).
50
Kumar, Dhananjay, Anjali Kapoor, Dharmendra Singh, Lopamudra Satapathy, Ashwini Kumar Singh, Manish Kumar, Kumble Vinod Prabhu i Kunal Mukhopadhyay. "Functional characterisation of a WRKY transcription factor of wheat and its expression analysis during leaf rust pathogenesis". Functional Plant Biology 41, nr 12 (2014): 1295. http://dx.doi.org/10.1071/fp14077.
Pełny tekst źródłaStreszczenie:
WRKY proteins are a large family of plant-specific transcription factors associated with regulation of biotic and abiotic stress responses, but how they respond to cereal rust pathogens has never been explored at the molecular level. Full-length cDNA of TaWRKY1B was obtained from a wheat cultivar HD2329 derivative containing leaf rust resistance gene Lr28 based on domain characteristics. The unique feature of this WRKY transcription factor gene was the close proximity of the DNA-binding domain and consensus DNA element W-Box within the open reading frame. Infection with a virulent race of leaf rust fungus resulted in 146-fold induction of the gene in resistant plants, but only 12-fold in the susceptible plants as compared with mock-inoculated controls. Docking models of 74 amino acids DNA-binding domain and 26 bp W-Box element showed that the WRKY domain, located on the β1 strand, only interacts with the W-Box at positions corresponding to W125, R126, K127 and Y128 amino acids. A truncated recombinant protein of 9.0 kD, encompassing the DNA-binding domain also showed binding specificity to the 32 bp W-Box element in electrophoretic mobility shift assays. The protein–DNA ensemble was also characterised using high-resolution atomic force microscopic imaging. The results contribute to an understanding of the molecular structure and function of a previously uncharacterised WRKY transcription factor in wheat that can be manipulated to improve biotic stress tolerance.