Journal articles on the topic 'Silence localization'
To see the other types of publications on this topic, follow the link: Silence localization.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Silence localization.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Thon, Geneviève, K. Pernilla Bjerling, and Inga Sig Nielsen. "Localization and Properties of a Silencing Element Near the mat3-M Mating-Type Cassette of Schizosaccharomyces pombe." Genetics 151, no. 3 (March 1, 1999): 945–63. http://dx.doi.org/10.1093/genetics/151.3.945.
Full textAbstract:
Abstract Transcription is repressed in a segment of Schizosaccharomyces pombe chromosome II that encompasses the mat2-P and mat3-M mating-type cassettes. Chromosomal deletion analysis revealed the presence of a repressor element within 500 bp of mat3-M. This element acted in synergy with the trans-acting factors Swi6, Clr1, Clr2, Clr3, and Clr4 and had several properties characteristic of silencers: it did not display promoter specificity, being able to silence not only the M mating-type genes but also the S. pombe ura4 and ade6 genes placed on the centromere-distal side of the mat3-M cassette; it could repress a gene when placed further than 2.6 kb from the promoter and it acted in both orientations, although with different efficiencies, the natural orientation repressing more stringently than the reverse. Following deletion of this element, two semistable states of expression of the mat3-M region were observed and these two states could interconvert. The deletion did not affect gene expression in the vicinity of the mat2-P cassette, 11 kb away from mat3-M. Conversely, deleting 1.5 kb on the centromere-proximal side of the mat2-P cassette, which was previously shown to partially derepress transcription around mat2-P, had no effect on gene expression near mat3-M. A double deletion removing the mat2-P and mat3-M repressor elements had the same effect as the single deletions on their respective cassettes when assayed in cells of the M mating type. These observations allow us to refine a model proposing that redundant pathways silence the mating type region of S. pombe.
2
Anton, Kristina, Arne Ernst, and Dietmar Basta. "A static sound source can improve postural stability during walking." Journal of Vestibular Research 31, no. 3 (May 5, 2021): 143–49. http://dx.doi.org/10.3233/ves-200015.
Full textAbstract:
BACKGROUND: During walking, postural stability is controlled by visual, vestibular and proprioceptive input. The auditory system uses acoustic input to localize sound sources. For some static balance conditions, the auditory influence on posture was already proven. Little is known about the impact of auditory inputs on balance in dynamic conditions. OBJECTIVE: This study is aimed at investigating postural stability of walking tasks in silence and sound on condition to better understand the impact of auditory input on balance in movement. METHODS: Thirty participants performed: walking (eyes open), tandem steps, walking with turning head and walking over barriers. During each task, acoustic condition changed between silence and presented noise through an earth-fixed loudspeaker located at the end of the walking distance. Body sway velocity was recorded close to the body’s center of gravity. RESULTS: A decreased body sway velocity was significant for walking (eyes open), tandem steps and walking over barriers when noise was presented. Those auditory stimuli did not affect sway velocity while walking with turning head. The posture has probably improved due to the localization ability when walking with the head facing forward, while the localization ability was impaired when turning the head. CONCLUSIONS: The localization ability of a fixed sound source through the auditory system has a significant but limited impact on posture while walking.
3
Kirkland, Jacob G., Misty R. Peterson, Christopher D. Still, Leo Brueggeman, Namrita Dhillon, and Rohinton T. Kamakaka. "Heterochromatin formation via recruitment of DNA repair proteins." Molecular Biology of the Cell 26, no. 7 (April 2015): 1395–410. http://dx.doi.org/10.1091/mbc.e14-09-1413.
Full textAbstract:
Heterochromatin formation and nuclear organization are important in gene regulation and genome fidelity. Proteins involved in gene silencing localize to sites of damage and some DNA repair proteins localize to heterochromatin, but the biological importance of these correlations remains unclear. In this study, we examined the role of double-strand-break repair proteins in gene silencing and nuclear organization. We find that the ATM kinase Tel1 and the proteins Mre11 and Esc2 can silence a reporter gene dependent on the Sir, as well as on other repair proteins. Furthermore, these proteins aid in the localization of silenced domains to specific compartments in the nucleus. We identify two distinct mechanisms for repair protein–mediated silencing—via direct and indirect interactions with Sir proteins, as well as by tethering loci to the nuclear periphery. This study reveals previously unknown interactions between repair proteins and silencing proteins and suggests insights into the mechanism underlying genome integrity.
4
Martin, Anna R., Camille M. Syrett, Arpita Myles, Michael L. Atchison, and Montserrat C. Anguera. "Atypical Xist RNA Localization to the Inactive X in a Female-biased Murine Model of Systemic Lupus Erythematosus." Journal of Immunology 200, no. 1_Supplement (May 1, 2018): 40.18. http://dx.doi.org/10.4049/jimmunol.200.supp.40.18.
Full textAbstract:
Abstract Systemic lupus erythematosus (SLE) is a severe autoimmune disease that affects women nine times more than men. The genetic basis for this bias is the X-chromosome, where the greatest concentration of immunity related genes on any chromosome can be found. Females have two X chromosomes (XX), and through a process, known as X-chromosome inactivation (XCI), silence one of their X-chromosomes randomly to have a similar level of X-linked gene expression as males (XY). In XCI, XIST RNA, a long non-coding RNA, is expressed from the future inactive X (Xi) and is bound to it in cis by the transcription factor YY1. As XIST coats the Xi, it recruits heterochromatin modifiers to condense and silence it. Previous research has shown that human SLE patient B cells exhibit altered localization of XIST RNA, thus indicating that they have partial reactivation of the Xi. To explore this relationship, we worked with NZB/W F1mice, which are a well-characterized murine model of SLE that also displays a female bias. The hypothesis of our study is that due to reduced expression of YY1, NZB/W F1 mice have altered Xist RNA localization leading to increased expression of X-linked genes in splenic B cells. Preliminary results using qPCR indicate that the concentration of YY1 is reduced across all stages of disease in NZB/W F1 when compared to age-matched wild type (WT) mice. Using Xist RNA FISH, we have observed that the activated B cells of late stage disease NZB/W F1 mice have decreased localization of Xist RNA to the Xi when compared to WT. In addition, we observed that the expression of TLR7 and CXCR3, two x-linked genes, are increased in diseased NZB/W F1 when compared to age-matched WT.
5
Rothé, Benjamin, Lucia Leal-Esteban, Florian Bernet, Séverine Urfer, Nicholas Doerr, Thomas Weimbs, Justyna Iwaszkiewicz, and Daniel B. Constam. "Bicc1 Polymerization Regulates the Localization and Silencing of Bound mRNA." Molecular and Cellular Biology 35, no. 19 (July 27, 2015): 3339–53. http://dx.doi.org/10.1128/mcb.00341-15.
Full textAbstract:
Loss of the RNA-binding protein Bicaudal-C (Bicc1) provokes renal and pancreatic cysts as well as ectopic Wnt/β-catenin signaling during visceral left-right patterning. Renal cysts are linked to defective silencing of Bicc1 target mRNAs, including adenylate cyclase 6 (AC6). RNA binding of Bicc1 is mediated by N-terminal KH domains, whereas a C-terminal sterile alpha motif (SAM) self-polymerizesin vitroand localizes Bicc1 in cytoplasmic fociin vivo. To assess a role for multimerization in silencing, we conducted structure modeling and then mutated the SAM domain residues which in this model were predicted to polymerize Bicc1 in a left-handed helix. We show that a SAM-SAM interface concentrates Bicc1 in cytoplasmic clusters to specifically localize and silence bound mRNA. In addition, defective polymerization decreases Bicc1 stability and thus indirectly attenuates inhibition of Dishevelled 2 in the Wnt/β-catenin pathway. Importantly, aberrant C-terminal extension of the SAM domain inbpkmutant Bicc1 phenocopied these defects. We conclude that polymerization is a novel disease-relevant mechanism both to stabilize Bicc1 and to present associated mRNAs in specific silencing platforms.
6
Zscheppang, Katja, Washa Liu, MaryAnn V. Volpe, Heber C. Nielsen, and Christiane E. L. Dammann. "ErbB4 regulates fetal surfactant phospholipid synthesis in primary fetal rat type II cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 293, no. 2 (August 2007): L429—L435. http://dx.doi.org/10.1152/ajplung.00451.2006.
Full textAbstract:
Insufficient fetal surfactant production leads to respiratory distress syndrome among preterm infants. Neuregulin signals the onset of fetal surfactant phospholipid synthesis through formation of erbB receptor dimers. We hypothesized that erbB4 downregulation in fetal type II epithelial cells will downregulate not only fetal surfactant phospholipid synthesis, but also affect proliferation and erbB receptor localization. We tested these hypotheses using small interfering RNA (siRNA) directed against the erbB4 gene to silence erbB4 receptor function in cultures of primary day 19 fetal rat lung type II cells. ErbB4 siRNA treatment inhibited erbB4 receptor protein expression, fibroblast-conditioned medium induced erbB4 phosphorylation, and fetal surfactant phospholipid synthesis. Cell proliferation, measured as thymidine incorporation, was also inhibited by erbB4 siRNA treatment. Downregulation of erbB4 receptor protein changed erbB1 localization at baseline and after stimulation, as determined by confocal microscopy and subcellular fractionation. We conclude that erbB4 is an important receptor in the control of fetal lung type II cell maturation.
7
Sateriale, Adam, Peter Miller, and Christopher D. Huston. "Knockdown of Five Genes Encoding Uncharacterized Proteins Inhibits Entamoeba histolytica Phagocytosis of Dead Host Cells." Infection and Immunity 84, no. 4 (January 25, 2016): 1045–53. http://dx.doi.org/10.1128/iai.01325-15.
Full textAbstract:
Entamoeba histolyticais the protozoan parasite that causes invasive amebiasis, which is endemic to many developing countries and characterized by dysentery and liver abscesses. The virulence ofE. histolyticacorrelates with the degree of host cell engulfment, or phagocytosis, andE. histolyticaphagocytosis alters amebic gene expression in a feed-forward manner that results in an increased phagocytic ability. Here, we used a streamlined RNA interference screen to silence the expression of 15 genes whose expression was upregulated in phagocyticE. histolyticatrophozoites to determine whether these genes actually function in the phagocytic process. When five of these genes were silenced, amebic strains with significant decreases in the ability to phagocytose apoptotic host cells were produced. Phagocytosis of live host cells, however, was largely unchanged, and the defects were surprisingly specific for phagocytosis. Two of the five encoded proteins, which we namedE. histolyticaILWEQ (EhILWEQ) andE. histolyticaBAR (EhBAR), were chosen for localization via SNAP tag labeling and localized to the site of partially formed phagosomes. Therefore, both EhILWEQ and EhBAR appear to contribute toE. histolyticavirulence through their function in phagocytosis, and the large proportion (5/15 [33%]) of gene-silenced strains with a reduced ability to phagocytose host cells validates the previously published microarray data set demonstrating feed-forward control ofE. histolyticaphagocytosis. Finally, although only limited conclusions can be drawn from studies using the virulence-deficient G3Entamoebastrain, the relative specificity of the defects induced for phagocytosis of apoptotic cells but not healthy cells suggests that cell killing may play a rate-limiting role in the process ofEntamoeba histolyticahost cell engulfment.
8
Curceanu, Catalina, Diana Sirghi, Florin Sirghi, Sergio Bartalucci, Massimiliano Bazzi, Alberto Clozza, Luca De Paolis, et al. "Quantum mechanics under X-rays in the Gran Sasso underground laboratory." International Journal of Quantum Information 15, no. 08 (December 2017): 1740004. http://dx.doi.org/10.1142/s0219749917400044.
Full textAbstract:
By performing X-ray measurements in the “cosmic silence” of the underground laboratory of Gran Sasso, LNGS-INFN, we test a basic principle of quantum mechanics: the Pauli Exclusion Principle (PEP) for electrons. We present the achieved results of the VIP experiment and the ongoing VIP2 measurement aiming to gain two orders of magnitude improvement in testing PEP. X-ray emission can also be used to put strong constraints on the parameters of the Continuous Spontaneous Localization Model, which was introduced as a possible solution to the measurement problem in Quantum Mechanics. A Bayesian analysis of the data collected by IGEX will be presented, which allows to exclude a broad region of the parameter space which characterizes this model.
9
Broad, Amanda J., and Jennifer G. DeLuca. "The right place at the right time: Aurora B kinase localization to centromeres and kinetochores." Essays in Biochemistry 64, no. 2 (May 14, 2020): 299–311. http://dx.doi.org/10.1042/ebc20190081.
Full textAbstract:
Abstract The fidelity of chromosome segregation during mitosis is intimately linked to the function of kinetochores, which are large protein complexes assembled at sites of centromeric heterochromatin on mitotic chromosomes. These key “orchestrators” of mitosis physically connect chromosomes to spindle microtubules and transduce forces through these connections to congress chromosomes and silence the spindle assembly checkpoint. Kinetochore-microtubule attachments are highly regulated to ensure that incorrect attachments are not prematurely stabilized, but instead released and corrected. The kinase activity of the centromeric protein Aurora B is required for kinetochore-microtubule destabilization during mitosis, but how the kinase acts on outer kinetochore substrates to selectively destabilize immature and erroneous attachments remains debated. Here, we review recent literature that sheds light on how Aurora B kinase is recruited to both centromeres and kinetochores and discuss possible mechanisms for how kinase interactions with substrates at distinct regions of mitotic chromosomes are regulated.
10
Michaud, Pascale, Vivek Nilesh Shah, Pauline Adjibade, Francois Houle, Miguel Quévillon Huberdeau, Rachel Rioux, Camille Lavoie-Ouellet, Weifeng Gu, Rachid Mazroui, and Martin J. Simard. "The RabGAP TBC-11 controls Argonaute localization for proper microRNA function in C. elegans." PLOS Genetics 17, no. 4 (April 7, 2021): e1009511. http://dx.doi.org/10.1371/journal.pgen.1009511.
Full textAbstract:
Once loaded onto Argonaute proteins, microRNAs form a silencing complex called miRISC that targets mostly the 3’UTR of mRNAs to silence their translation. How microRNAs are transported to and from their target mRNA remains poorly characterized. While some reports linked intracellular trafficking to microRNA activity, it is still unclear how these pathways coordinate for proper microRNA-mediated gene silencing and turnover. Through a forward genetic screen usingCaenorhabditis elegans, we identified the RabGAPtbc-11as an important factor for the microRNA pathway. We show that TBC-11 acts mainly through the small GTPase RAB-6 and that its regulation is required for microRNA function. The absence of functional TBC-11 increases the pool of microRNA-unloaded Argonaute ALG-1 that is likely associated to endomembranes. Furthermore, in this condition, this pool of Argonaute accumulates in a perinuclear region and forms a high molecular weight complex. Altogether, our data suggest that the alteration of TBC-11 generates a fraction of ALG-1 that cannot bind to target mRNAs, leading to defective gene repression. Our results establish the importance of intracellular trafficking for microRNA function and demonstrate the involvement of a small GTPase and its GAP in proper Argonaute localizationin vivo.
11
Rodermund, Lisa, Heather Coker, Roel Oldenkamp, Guifeng Wei, Joseph Bowness, Bramman Rajkumar, Tatyana Nesterova, David Miguel Susano Pinto, Lothar Schermelleh, and Neil Brockdorff. "Time-resolved structured illumination microscopy reveals key principles of Xist RNA spreading." Science 372, no. 6547 (June 10, 2021): eabe7500. http://dx.doi.org/10.1126/science.abe7500.
Full textAbstract:
X-inactive specific transcript (Xist) RNA directs the process of X chromosome inactivation in mammals by spreading in cis along the chromosome from which it is transcribed and recruiting chromatin modifiers to silence gene transcription. To elucidate mechanisms of Xist RNA cis-confinement, we established a sequential dual-color labeling, super-resolution imaging approach to trace individual Xist RNA molecules over time, which enabled us to define fundamental parameters of spreading. We demonstrate a feedback mechanism linking Xist RNA synthesis and degradation and an unexpected physical coupling between preceding and newly synthesized Xist RNA molecules. Additionally, we find that the protein SPEN, a key factor for Xist-mediated gene silencing, has a distinct function in Xist RNA localization, stability, and coupling behaviors. Our results provide insights toward understanding the distinct dynamic properties of Xist RNA.
12
Karpenko, Gennady Yu. "About “Realisms” (Story by O. N. Olnem А Quiet Corner and Literary Memoirs of Sergey Durylin In the Native Corner)." Проблемы исторической поэтики 18, no. 3 (July 2020): 221–47. http://dx.doi.org/10.15393/j9.art.2020.7982.
Full textAbstract:
<p>The article studies and compares various possibilities of Russian classical realism, it reveals and describes the features of constructing images of the world in the works of O. N. Olnem (V. N. Tsekhovskaya) and S. N. Durylin. The pictures of the world by Olnem and Durylin are limited mainly by the manor topos. Localization of the events within the manor space is the key for the presence of the same objective and spiritual realities in the analyzed works, nevertheless, distributed and correlated differently. While the “narrative levels” in Durylin’s memoirs (subject, functional, socio-historical, subjective-personal, cultural-historical, Christian ones) are value-coordinative and the Orthodox determines theoanthropic “verticality” of the estate world, in Olnem’s description all the “estate elements” are coordinate and exist in the horizon of a personal or social event, they are factographic, only psychologically and / or socially colored, and the “Christian event lasting in eternity” loses its world-organizing function and is present as a formal rhetorical tradition. The difference in the actualization by Olnem and Durylin of the value of narrative levels is expressed in the implied meanings of the name — <em>A Quiet Corner</em>, <em>In the Home Corner</em>. The writers relate the “Manor Corner” to silence. However, if for Durylin the “quiet”, “silence” is a spiritual complex that expresses the Christ-like essence of a person, for Olnem, silence is a socio-historical category, designed to mark semantically the process of disappearance of the “noble nest,” silence as a synonym for death. Thus, no matter how close the work of the writers came together in substantive content, no matter how similar and related they were, the “watershed” separating them, in the words of V. V. Rozanov, turns out to be the “attitude to faith, God”. This difference determines the existence of different "realisms" in Russian literature and, consequently, of different reading and research strategies.</p>
13
Firestein, Ron, Xiangmin Cui, Phil Huie, and Michael L. Cleary. "Set Domain-Dependent Regulation of Transcriptional Silencing and Growth Control by SUV39H1, a Mammalian Ortholog ofDrosophila Su(var)3-9." Molecular and Cellular Biology 20, no. 13 (July 1, 2000): 4900–4909. http://dx.doi.org/10.1128/mcb.20.13.4900-4909.2000.
Full textAbstract:
ABSTRACT Mammalian SET domain-containing proteins define a distinctive class of chromatin-associated factors that are targets for growth control signals and oncogenic activation. SUV39H1, a mammalian ortholog ofDrosophila Su(var)3-9, contains both SET and chromo domains, signature motifs for proteins that contribute to epigenetic control of gene expression through effects on the regional organization of chromatin structure. In this report we demonstrate that SUV39H1 represses transcription in a transient transcriptional assay when tethered to DNA through the GAL4 DNA binding domain. Under these conditions, SUV39H1 displays features of a long-range repressor capable of acting over several kilobases to silence basal promoters. A possible role in chromatin-mediated gene silencing is supported by the localization of exogenously expressed SUV39H1 to nuclear bodies with morphologic features suggestive of heterochromatin in interphase cells. In addition, we show that SUV39H1 is phosphorylated specifically at the G1/S cell cycle transition and when forcibly expressed suppresses cell growth. Growth suppression as well as the ability of SUV39H1 to form nuclear bodies and silence transcription are antagonized by the oncogenic antiphosphatase Sbf1 that when hyperexpressed interacts with the SET domain and stabilizes the phosphorylated form of SUV39H1. These studies suggest a phosphorylation-dependent mechanism for regulating the chromatin organizing activity of a mammalian su(var) protein and implicate the SET domain as a gatekeeper motif that integrates upstream signaling pathways to epigenetic regulation and growth control.
14
Shestakova, E. A., and T. A. Bogush. "BRCa1 participates in XIST RNa localization on inactive x chromosome." Russian Journal of Biotherapy 18, no. 2 (June 15, 2019): 21–26. http://dx.doi.org/10.17650/1726-9784-2019-18-2-21-26.
Full textAbstract:
Introduction . Inactive X chromosome (Xi) is associated with noncoding XIST RNA, series of proteins and contains multiple epigenetic modifications that altogether determine a silence of the most of X-linked genes. Recently the data were obtained that tumor suppressor BRCA1 is also associated with Xi. The purpose of this study was to reveal the colocalization of BRCA1 and XIST RNA and precise spatial organization on Xi with the high resolution of confocal microscopy.Materials and methods . The object of the study is IMR90hTERT diploid immortalized fibroblast cell line. For BRCA1 and XIST RNA colocalization analysis on Xi the method of fluorescent hybridization in situ associated with immunofluorescent cell staining (immunoFISH) and confocal microscopy were used. For BRCA1 and heterochromatin protein-1 colocalization study the method of double immunofluorescent staining and common fluorescent microscopy were applied. Results . The study using confocal fluorescent microscopy with higher resolution has demonstrated at first the colocalization of BRCA1 with XIST RNA region of Xi revealed with XIST RNA probes and with replicating Xi and autosomes revealed with BrdU in late S-phase of cell cycle. Altogether, the data obtained suggest the involvement of BRCA1 in the inhibition of gene expression on Xi due to the regulation of XIST RNA association with Xi. Moreover, according to the results of confocal microscopy, BRCA1 also colocalizes with replicating Xi and autosomes revealed with BrdU in late S-phase of cell cycle. This indicates a possible involvement of this protein in the replication of pericentromeric repeats in cellular chromosomes. Colocalization of BRCA1 with heterochromatin protein-1α presented in pericentromeric regions of all chromosomes supports this suggestion.Conclusions . Altogether, the data obtained in this study suggest the involvement of BRCA1 in the inhibition of gene expression on Xi due to the association with noncoding inhibiting XIST RNA and in replication of heterochromatin regions.
15
Zhou, Xi’nan, Yangyang Zheng, Zhibo Cai, Xingyuan Wang, Yang Liu, Anzhou Yu, Xiuling Chen, Jiayin Liu, Yao Zhang, and Aoxue Wang. "Identification and Functional Analysis of Tomato TPR Gene Family." International Journal of Molecular Sciences 22, no. 2 (January 13, 2021): 758. http://dx.doi.org/10.3390/ijms22020758.
Full textAbstract:
Tomato (Solanum lycopersicum) as an important vegetable grown around the world is threatened by many diseases, which seriously affects its yield. Therefore, studying the interaction between tomato and pathogenic bacteria is biologically and economically important. The TPR (Tetratricopeptide repeat) gene family is a class of genes containing TPR conserved motifs, which are widely involved in cell cycle regulation, gene expression, protein degradation and other biological processes. The functions of TPR gene in Arabidopsis and wheat plants have been well studied, but the research on TPR genes in tomato is not well studied. In this study, 26 TPR gene families were identified using bioinformatics based on tomato genome data, and they were analyzed for subcellular localization, phylogenetic evolution, conserved motifs, tissue expression, and GO (Gene Ontology) analysis. The qRT-PCR was used to detect the expression levels of each member of the tomato TPR gene family (SlTPRs) under biological stress (Botrytis cinerea) and abiotic stress such as drought and abscisic acid (ABA). The results showed that members of the tomato TPR family responded to various abiotic stresses and Botrytis cinerea stress, and the SlTPR2 and SlTPR4 genes changed significantly under different stresses. Using VIGS (Virus-induced gene silencing) technology to silence these two genes, the silenced plants showed reduced disease resistance. It was also shown that TPR4 can interact with atpA which encodes a chloroplast ATP synthase CF1 α subunit. The above results provide a theoretical basis for further exploring the molecular mechanism of TPR-mediated resistance in disease defense, and also provide a foundation for tomato disease resistance breeding.
16
Zhang, Dong, Shen Yin, Man-Xi Jiang, Wei Ma, Yi Hou, Cheng-Guang Liang, Ling-Zhu Yu, Wei-Hua Wang, and Qing-Yuan Sun. "Cytoplasmic dynein participates in meiotic checkpoint inactivation in mouse oocytes by transporting cytoplasmic mitotic arrest-deficient (Mad) proteins from kinetochores to spindle poles." Reproduction 133, no. 4 (April 2007): 685–95. http://dx.doi.org/10.1530/rep.1.01167.
Full textAbstract:
The present study was designed to investigate the localization and function of cytoplasmic dynein (dynein) during mouse oocyte meiosis and its relationship with two major spindle checkpoint proteins, mitotic arrest-deficient (Mad) 1 and Mad2. Oocytes at various stages during the first meiosis were fixed and immunostained for dynein, Mad1, Mad2, kinetochores, microtubules, and chromosomes. Some oocytes were treated with nocodazole before examination. Anti-dynein antibody was injected into the oocytes at germinal vesicle (GV) stage before the examination of its effects on meiotic progression or Mad1 and Mad2 localization. Results showed that dynein was present in the oocytes at various stages from GV to metaphase II and the locations of Mad1 and Mad2 were associated with dynein’s movement. Both Mad1 and Mad2 had two existing states: one existed in the cytoplasm (cytoplasmic Mad1 or cytoplasmic Mad2), which did not bind to kinetochores, while the other bound to kinetochores (kinetochore Mad1 or kinetochore Mad2). The equilibrium between the two states varied during meiosis and/or in response to the changes of the connection between microtubules and kinetochores. Cytoplasmic Mad1 and Mad2 recruited to chromosomes when the connection between microtubules and chromosomes was destroyed. Inhibition of dynein interferes with cytoplasmic Mad1 and Mad2 transportation from chromosomes to spindle poles, thus inhibits checkpoint silence and delays anaphase onset. These results indicate that dynein may play a role in spindle checkpoint inactivation.
17
Shareef, Mohammed Momin, Chadwick King, Mona Damaj, RamaKrishna Badagu, Da Wei Huang, and Rebecca Kellum. "DrosophilaHeterochromatin Protein 1 (HP1)/Origin Recognition Complex (ORC) Protein Is Associated with HP1 and ORC and Functions in Heterochromatin-induced Silencing." Molecular Biology of the Cell 12, no. 6 (June 2001): 1671–85. http://dx.doi.org/10.1091/mbc.12.6.1671.
Full textAbstract:
Heterochromatin protein 1 (HP1) is a conserved component of the highly compact chromatin of higher eukaryotic centromeres and telomeres. Cytogenetic experiments in Drosophila have shown that HP1 localization into this chromatin is perturbed in mutants for the origin recognition complex (ORC) 2 subunit. ORC has a multisubunit DNA-binding activity that binds origins of DNA replication where it is required for origin firing. The DNA-binding activity of ORC is also used in the recruitment of the Sir1 protein to silence nucleation sites flanking silent copies of the mating-type genes inSaccharomyces cerevisiae. A fraction of HP1 in the maternally loaded cytoplasm of the early Drosophilaembryo is associated with a multiprotein complex containingDrosophila melanogaster ORC subunits. This complex appears to be poised to function in heterochromatin assembly later in embryonic development. Here we report the identification of a novel component of this complex, the HP1/ORC-associated protein. This protein contains similarity to DNA sequence-specific HMG proteins and is shown to bind specific satellite sequences and the telomere-associated sequence in vitro. The protein is shown to have heterochromatic localization in both diploid interphase and mitotic chromosomes and polytene chromosomes. Moreover, the gene encoding HP1/ORC-associated protein was found to display reciprocal dose-dependent variegation modifier phenotypes, similar to those for mutants in HP1 and the ORC 2 subunit.
18
Mensa-Wilmot, K., D. Hereld, and P. T. Englund. "Genomic organization, chromosomal localization, and developmentally regulated expression of the glycosyl-phosphatidylinositol-specific phospholipase C of Trypanosoma brucei." Molecular and Cellular Biology 10, no. 2 (February 1990): 720–26. http://dx.doi.org/10.1128/mcb.10.2.720-726.1990.
Full textAbstract:
The surface of the bloodstream form of the African trypanosome, Trypansoma brucei, is covered with about 10(7) molecules of the variant surface glycoprotein (VSG), a protein tethered to the plasma membrane by a glycosyl-phosphatidylinositol (GPI) membrane anchor. This anchor is cleavable by an endogenous GPI-specific phospholipase C (GPI-PLC). GPI-PLC activity is down regulated when trypanosomes differentiate from the bloodstream form to the procyclic form found in the tsetse fly vector. We have mapped the GPI-PLC locus in the trypanosome genome and have examined the mechanism for this developmental regulation in T. brucei. Southern blot analysis indicates a single-copy gene for GPI-PLC, with two allelic variants distinguishable by two NcoI restriction fragment length polymorphisms. The gene was localized solely to a chromosome in the two-megabase compression region by contour-clamped homogeneous electric field gel electrophoresis. No rearrangement of the GPI-PLC gene occurs during differentiation to procyclic forms, which could potentially silence GPI-PLC gene expression. Enzymological studies give no indication of a diffusible inhibitor of GPI-PLC activity in procyclic forms, and Western immunoblot analysis reveals no detectable GPI-PLC polypeptide in these forms. Therefore, it is highly unlikely that the absence of GPI-PLC activity in procyclic forms is due to posttranslational control. Northern (RNA) blot analysis reveals barely detectable levels of GPI-PLC mRNA in procyclic forms; therefore, regulation of GPI-PLC activity in these forms correlates with the steady-state mRNA level.
19
Mensa-Wilmot, K., D. Hereld, and P. T. Englund. "Genomic organization, chromosomal localization, and developmentally regulated expression of the glycosyl-phosphatidylinositol-specific phospholipase C of Trypanosoma brucei." Molecular and Cellular Biology 10, no. 2 (February 1990): 720–26. http://dx.doi.org/10.1128/mcb.10.2.720.
Full textAbstract:
The surface of the bloodstream form of the African trypanosome, Trypansoma brucei, is covered with about 10(7) molecules of the variant surface glycoprotein (VSG), a protein tethered to the plasma membrane by a glycosyl-phosphatidylinositol (GPI) membrane anchor. This anchor is cleavable by an endogenous GPI-specific phospholipase C (GPI-PLC). GPI-PLC activity is down regulated when trypanosomes differentiate from the bloodstream form to the procyclic form found in the tsetse fly vector. We have mapped the GPI-PLC locus in the trypanosome genome and have examined the mechanism for this developmental regulation in T. brucei. Southern blot analysis indicates a single-copy gene for GPI-PLC, with two allelic variants distinguishable by two NcoI restriction fragment length polymorphisms. The gene was localized solely to a chromosome in the two-megabase compression region by contour-clamped homogeneous electric field gel electrophoresis. No rearrangement of the GPI-PLC gene occurs during differentiation to procyclic forms, which could potentially silence GPI-PLC gene expression. Enzymological studies give no indication of a diffusible inhibitor of GPI-PLC activity in procyclic forms, and Western immunoblot analysis reveals no detectable GPI-PLC polypeptide in these forms. Therefore, it is highly unlikely that the absence of GPI-PLC activity in procyclic forms is due to posttranslational control. Northern (RNA) blot analysis reveals barely detectable levels of GPI-PLC mRNA in procyclic forms; therefore, regulation of GPI-PLC activity in these forms correlates with the steady-state mRNA level.
20
Lee, Song Hee, Katie Caviness, Emily R. Albright, Jeong-Hee Lee, Christopher B. Gelbmann, Mike Rak, Felicia Goodrum, and Robert F. Kalejta. "Long and Short Isoforms of the Human Cytomegalovirus UL138 Protein Silence IE Transcription and Promote Latency." Journal of Virology 90, no. 20 (August 10, 2016): 9483–94. http://dx.doi.org/10.1128/jvi.01547-16.
Full textAbstract:
ABSTRACTThe UL133–138 locus present in clinical strains of human cytomegalovirus (HCMV) encodes proteins required for latency and reactivation in CD34+hematopoietic progenitor cells and virion maturation in endothelial cells. The encoded proteins form multiple homo- and hetero-interactions and localize within secretory membranes. One of these genes, UL136 gene, is expressed as at least five different protein isoforms with overlapping and unique functions. Here we show that another gene from this locus, the UL138 gene, also generates more than one protein isoform. A long form of UL138 (pUL138-L) initiates translation from codon 1, possesses an amino-terminal signal sequence, and is a type one integral membrane protein. Here we identify a short protein isoform (pUL138-S) initiating from codon 16 that displays a subcellular localization similar to that of pUL138-L. Reporter, short-term transcription, and long-term virus production assays revealed that both pUL138-L and pUL138-S are able to suppress major immediate early (IE) gene transcription and the generation of infectious virions in cells in which HCMV latency is studied. The long form appears to be more potent at silencing IE transcription shortly after infection, while the short form seems more potent at restricting progeny virion production at later times, indicating that both isoforms of UL138 likely cooperate to promote HCMV latency.IMPORTANCELatency allows herpesviruses to persist for the lives of their hosts in the face of effective immune control measures for productively infected cells. Controlling latent reservoirs is an attractive antiviral approach complicated by knowledge deficits for how latently infected cells are established, maintained, and reactivated. This is especially true for betaherpesviruses. The functional consequences of HCMV UL138 protein expression during latency include repression of viral IE1 transcription and suppression of virus replication. Here we show that short and long isoforms of UL138 exist and can themselves support latency but may do so in temporally distinct manners. Understanding the complexity of gene expression and its impact on latency is important for considering potential antivirals targeting latent reservoirs.
21
Harðardóttir, Hulda María, Rune Male, Frank Nilsen, and Sussie Dalvin. "Chitin Synthases Are Critical for Reproduction, Molting, and Digestion in the Salmon Louse (Lepeophtheirus salmonis)." Life 11, no. 1 (January 13, 2021): 47. http://dx.doi.org/10.3390/life11010047.
Full textAbstract:
Chitin synthase (CHS) is a large transmembrane enzyme that polymerizes Uridine diphosphate N-acetylglucosamine into chitin. The genomes of insects often encode two chitin synthases, CHS1 and CHS2. Their functional roles have been investigated in several insects: CHS1 is mainly responsible for synthesizing chitin in the cuticle and CHS2 in the midgut. Lepeophtheirus salmonis is an ectoparasitic copepod on salmonid fish, which causes significant economic losses in aquaculture. In the present study, the tissue-specific localization, expression, and functional role of L. salmonis chitin synthases, LsCHS1 and LsCHS2, were investigated. The expressions of LsCHS1 and LsCHS2 were found in oocytes, ovaries, intestine, and integument. Wheat germ agglutinin (WGA) chitin staining signals were detected in ovaries, oocytes, intestine, cuticle, and intestine in adult female L. salmonis. The functional roles of the LsCHSs were investigated using RNA interference (RNAi) to silence the expression of LsCHS1 and LsCHS2. Knockdown of LsCHS1 in pre-adult I lice resulted in lethal phenotypes with cuticle deformation and deformation of ovaries and oocytes in adult lice. RNAi knockdown of LsCHS2 in adult female L. salmonis affected digestion, damaged the gut microvilli, reduced muscular tissues around the gut, and affected offspring. The results demonstrate that both LsCHS1 and LsCHS2 are important for the survival and reproduction in L. salmonis.
22
de Ronde-Brons, Inge, Wim Soede, and Wouter Dreschler. "Systematic Evaluation of Self-Reported Hearing Ability in Six Dimensions Before and After a Hearing Aid Trial." Journal of Speech, Language, and Hearing Research 62, no. 11 (November 22, 2019): 4150–64. http://dx.doi.org/10.1044/2019_jslhr-h-19-0169.
Full textAbstract:
Purpose The aim of the study was to evaluate the application of a modified version of the Amsterdam Inventory for Auditory Disabilities and Handicap to inventory self-reported hearing difficulties pre and post hearing aid fitting in 6 dimensions: detection, speech in silence, speech in noise, localization, discrimination, and noise tolerance. Method Questionnaires pre and post hearing aid fitting were collected during regular practice of hearing aid provision. Data of 740 subjects are presented; 337 already used hearing aids, and 403 were new users. Results Group-averaged scores improved due to hearing aid fitting for all 6 dimensions. Based on a criterion previously defined for the Amsterdam Inventory for Auditory Disabilities and Handicap questionnaire, 66% of subjects had a significant individual improvement in sum score. Experienced users showed lower improvement in scores, whereas their aided prescores were, on average, not better than the (unaided) score of 1st users. Conclusions The questionnaire can be applied as a structured approach to inventory hearing problems in 6 dimensions prior to hearing aid fitting and to systematically evaluate the effects of hearing aid fitting after a trial period. The data presented here can serve as normative data for comparison of individual subjects in clinical practice.
23
Creamer, K. M., and J. B. Lawrence. "XIST RNA: a window into the broader role of RNA in nuclear chromosome architecture." Philosophical Transactions of the Royal Society B: Biological Sciences 372, no. 1733 (September 25, 2017): 20160360. http://dx.doi.org/10.1098/rstb.2016.0360.
Full textAbstract:
XIST RNA triggers the transformation of an active X chromosome into a condensed, inactive Barr body and therefore provides a unique window into transitions of higher-order chromosome architecture. Despite recent progress, how XIST RNA localizes and interacts with the X chromosome remains poorly understood. Genetic engineering of XIST into a trisomic autosome demonstrates remarkable capacity of XIST RNA to localize and comprehensively silence that autosome. Thus, XIST does not require X chromosome-specific sequences but operates on mechanisms available genome-wide. Prior results suggested XIST localization is controlled by attachment to the insoluble nuclear scaffold. Our recent work affirms that scaffold attachment factor A (SAF-A) is involved in anchoring XIST , but argues against the view that SAF-A provides a unimolecular bridge between RNA and the chromosome. Rather, we suggest that a complex meshwork of architectural proteins interact with XIST RNA. Parallel work studying the territory of actively transcribed chromosomes suggests that repeat-rich RNA ‘coats’ euchromatin and may impact chromosome architecture in a manner opposite of XIST . A model is discussed whereby RNA may not just recruit histone modifications, but more directly impact higher-order chromatin condensation via interaction with architectural proteins of the nucleus. This article is part of the themed issue ‘X-chromosome inactivation: a tribute to Mary Lyon’.
24
Penkert, Rhiannon R., and Robert F. Kalejta. "Nuclear Localization of Tegument-Delivered pp71 in Human Cytomegalovirus-Infected Cells Is Facilitated by One or More Factors Present in Terminally Differentiated Fibroblasts." Journal of Virology 84, no. 19 (August 4, 2010): 9853–63. http://dx.doi.org/10.1128/jvi.00500-10.
Full textAbstract:
ABSTRACT Herpesviral virions contain a tegument layer that consists primarily of viral proteins. The delivery of fully functional proteins to infected cells upon virion envelope fusion to the plasma membrane allows herpesviruses to modulate cellular activities prior to viral gene expression. Certain tegument proteins can also regulate viral processes. For example, the pp71 tegument protein encoded by the UL82 gene of human cytomegalovirus (HCMV) stimulates viral immediate early (IE) gene expression and thus acts to initiate the productive lytic infectious cycle. In terminally differentiated fibroblasts infected with HCMV, tegument-delivered pp71 traffics to the nucleus and degrades the cellular transcriptional corepressor Daxx to initiate viral IE gene expression and lytic replication. However, when HCMV infects incompletely differentiated cells, tegument-delivered pp71 remains in the cytoplasm, allowing the nucleus-localized Daxx protein to silence viral IE gene expression and promote the establishment of a latent infection in certain cell types. We sought to determine whether undifferentiated cells block the trafficking of tegument-delivered pp71 to the nucleus or whether differentiated cells facilitate the nuclear transport of tegument-delivered pp71. Heterogenous cell fusion experiments demonstrated that tegument-delivered pp71 found in the cytoplasm of undifferentiated NT2 cells could be driven into the nucleus by one or more factors provided by fully differentiated fibroblasts. Our data raise the intriguing possibility that latency is the default program launched by HCMV upon viral entry into cells and that lytic infection is initiated only in certain (differentiated) cells that can facilitate the delivery of incoming pp71 to the nucleus.
25
Blum Moyse, Lisa, and Hugues Berry. "Modelling the modulation of cortical Up-Down state switching by astrocytes." PLOS Computational Biology 18, no. 7 (July 21, 2022): e1010296. http://dx.doi.org/10.1371/journal.pcbi.1010296.
Full textAbstract:
Up-Down synchronization in neuronal networks refers to spontaneous switches between periods of high collective firing activity (Up state) and periods of silence (Down state). Recent experimental reports have shown that astrocytes can control the emergence of such Up-Down regimes in neural networks, although the molecular or cellular mechanisms that are involved are still uncertain. Here we propose neural network models made of three populations of cells: excitatory neurons, inhibitory neurons and astrocytes, interconnected by synaptic and gliotransmission events, to explore how astrocytes can control this phenomenon. The presence of astrocytes in the models is indeed observed to promote the emergence of Up-Down regimes with realistic characteristics. Our models show that the difference of signalling timescales between astrocytes and neurons (seconds versus milliseconds) can induce a regime where the frequency of gliotransmission events released by the astrocytes does not synchronize with the Up and Down phases of the neurons, but remains essentially stable. However, these gliotransmission events are found to change the localization of the bifurcations in the parameter space so that with the addition of astrocytes, the network enters a bistability region of the dynamics that corresponds to Up-Down synchronization. Taken together, our work provides a theoretical framework to test scenarios and hypotheses on the modulation of Up-Down dynamics by gliotransmission from astrocytes.
26
Enwright, John F., Margaret A. Kawecki-Crook, Ty C. Voss, Fred Schaufele, and Richard N. Day. "A PIT-1 Homeodomain Mutant Blocks the Intranuclear Recruitment Of the CCAAT/Enhancer Binding Protein α Required for Prolactin Gene Transcription." Molecular Endocrinology 17, no. 2 (February 1, 2003): 209–22. http://dx.doi.org/10.1210/me.2001-0222.
Full textAbstract:
Abstract The pituitary-specific homeodomain protein Pit-1 cooperates with other transcription factors, including CCAAT/enhancer binding protein α (C/EBPα), in the regulation of pituitary lactotrope gene transcription. Here, we correlate cooperative activation of prolactin (PRL) gene transcription by Pit-1 and C/EBPα with changes in the subnuclear localization of these factors in living pituitary cells. Transiently expressed C/EBPα induced PRL gene transcription in pituitary GHFT1–5 cells, whereas the coexpression of Pit-1 and C/EBPα in HeLa cells demonstrated their cooperativity at the PRL promoter. Individually expressed Pit-1 or C/EBPα, fused to color variants of fluorescent proteins, occupied different subnuclear compartments in living pituitary cells. When coexpressed, Pit-1 recruited C/EBPα from regions of transcriptionally quiescent centromeric heterochromatin to the nuclear regions occupied by Pit-1. The homeodomain region of Pit-1 was necessary for the recruitment of C/EBPα. A point mutation in the Pit-1 homeodomain associated with the syndrome of combined pituitary hormone deficiency in humans also failed to recruit C/EBPα. This Pit-1 mutant functioned as a dominant inhibitor of PRL gene transcription and, instead of recruiting C/EBPα, was itself recruited by C/EBPα to centromeric heterochromatin. Together our results suggest that the intranuclear positioning of these factors determines whether they activate or silence PRL promoter activity.
27
Alinari, Lapo, Fengting Yan, Porsha Smith, John T. Patton, Carl Quinion, Bo Yu, Christian Tyler Earl, et al. "Protein Arginine Methyltransferase 5 (PRMT5) Over-Expression Is Essential for Epstein-Barr Virus-Driven B-Cell Transformation." Blood 120, no. 21 (November 16, 2012): 2378. http://dx.doi.org/10.1182/blood.v120.21.2378.2378.
Full textAbstract:
Abstract Abstract 2378 Epstein-Barr virus (EBV) is a ubiquitous, gamma herpes virus that infects human epithelial cells and B lymphocytes. Over 90% of adults worldwide are infected with EBV and, collectively, this virus is associated with a broad spectrum of benign and malignant disease. EBV is a potent oncogenic virus and is capable of efficiently transforming B cells in both in vitro and in vivo models. While signaling cascades contributing toward B cell immortalization and transformation following EBV infection have been described, epigenetic events that contribute toward the B cell transformation process remain poorly characterized. EBV-transformed lymphoblastoid lines (LCL) and spontaneous B cell lymphomas that arise in the hu-PBL-SCID model of EBV-induced lymphomagenesis show abundant expression of the protein arginine methyltransferase 5 (PRMT5), a type II PRMT enzyme that catalyzes symmetric dimethylation of arginine residues on histones and non histone proteins (P53, CYCLIN D1). PRMT5 partners with multiple co-repressor proteins such as HDAC2, MBD2 and DNMT3a to silence multiple regulatory and tumor suppressor gene products. All EBV-transformed B cell lines and primary tumors showed cytoplasmic and nuclear staining for PRMT5 and its associated epigenetic marks symmetric dimethyl histone 3, arginine 8 (S2Me-H3R8) and S2Me-H4R3. Resting and activated B cells did not demonstrate PRMT5 over expression or associated global epigenetic marks. Infection of primary human B cells with the B95.8 strain (but not mutant P3HR1 or inactivated EBV) led to dysregulated expression of PRMT5 as early as day 4 post infection. By day 8 post EBV infection, PRMT5 location had transitioned to the nucleus and this localization coincided with acquisition of S2Me-H4R3 and S2Me-H3R8 and loss of the asymmetric epigenetic mark 2Me-H4R3,a type I PRMT histone mark. PRMT5 over-expression was dependent on LMP-1-driven NFkB activity and transcriptional silencing of miR96 expression, a micro RNA that targets the PRMT5 3'UTR. To determine if PRMT5 over expression was essential for induction and maintenance of the transformed phenotype, we infected resting B cells with EBV and, at various time points (day 4, 7, 14 or 21), added a novel, highly selective small molecule inhibitor of PRMT5 activity, an inactive small molecule control, shRNA specific for PRMT5 or control shRNA. Absolute CD19+ cell counts and confocal microscopy experiments to monitor PRMT5 and its epigenetic marks were performed and showed that PRMT5 activity was critical for EBV-driven B cell transformation to proceed. PRMT5 inhibition of resting or activated B cells did not result in any loss of viability. Global transcriptome analysis identified several tumor suppressor genes, including the protein tyrosine phosphatase PTPROt, were silenced during EBV-driven B cell transformation. Chromatin immune precipitation (ChIP)-sequencing using monoclonal antibodies specific for PMRT5 and S2Me-H3R8 (or control IgG) confirmed the PTPROt promoter to be directly targeted by PRMT5 and PTPROt transcript was found to become silenced during EBV-driven B cell transformation. Real time PCR and RNA-seq showed PTPROt transcript to become restored with PRMT5 inhibition. PTPROt expression led to dephosphorylation and inhibition of the LYN, SYK, and Bruton's Tyrosine kinase (BTK) kinase proteins, critical proteins involved in regulation of the B cell receptor (BCR). This model provided us with direct evidence that PRMT5 activity is critical to EBV-driven B cell transformation and supports our hypothesis that PRMT5 dysregulation drives epigenetic events that directly contribute to key initiating events during B cell transformation as well as to the maintenance of the malignant phenotype. We believe this is the first example of oncogenic virus driving over expression of an epigenetic modifier that catalyzes placement of global repressive epigenetic marks that silence of regulatory and tumor suppressor genes. This data justifies pursuit of experimental therapeutic strategies focused on selective PRMT5 inhibition in cancer. Disclosures: No relevant conflicts of interest to declare.
28
Khan, Md Abdullah Al Hafiz, Nirmalya Roy, and H. M. Sajjad Hossain. "Wearable Sensor-Based Location-Specific Occupancy Detection in Smart Environments." Mobile Information Systems 2018 (2018): 1–21. http://dx.doi.org/10.1155/2018/4570182.
Full textAbstract:
Occupancy detection helps enable various emerging smart environment applications ranging from opportunistic HVAC (heating, ventilation, and air-conditioning) control, effective meeting management, healthy social gathering, and public event planning and organization. Ubiquitous availability of smartphones and wearable sensors with the users for almost 24 hours helps revitalize a multitude of novel applications. The inbuilt microphone sensor in smartphones plays as an inevitable enabler to help detect the number of people conversing with each other in an event or gathering. A large number of other sensors such as accelerometer and gyroscope help count the number of people based on other signals such as locomotive motion. In this work, we propose multimodal data fusion and deep learning approach relying on the smartphone’s microphone and accelerometer sensors to estimate occupancy. We first demonstrate a novel speaker estimation algorithm for people counting and extend the proposed model using deep nets for handling large-scale fluid scenarios with unlabeled acoustic signals. We augment our occupancy detection model with a magnetometer-dependent fingerprinting-based localization scheme to assimilate the volume of location-specific gathering. We also propose crowdsourcing techniques to annotate the semantic location of the occupant. We evaluate our approach in different contexts: conversational, silence, and mixed scenarios in the presence of 10 people. Our experimental results on real-life data traces in natural settings show that our cross-modal approach can achieve approximately 0.53 error count distance for occupancy detection accuracy on average.
29
Wang, Xiaojian, Nan Li, Bin Liu, Hongying Sun, Taoyong Chen, Hongzhe Li, Jianming Qiu, Lihuang Zhang, Tao Wan, and Xuetao Cao. "A Novel Human Phosphatidylethanolamine-binding Protein Resists Tumor Necrosis Factor α-induced Apoptosis by Inhibiting Mitogen-activated Protein Kinase Pathway Activation and Phosphatidylethanolamine Externalization." Journal of Biological Chemistry 279, no. 44 (August 9, 2004): 45855–64. http://dx.doi.org/10.1074/jbc.m405147200.
Full textAbstract:
The phosphatidylethanolamine (PE)-binding proteins (PEBPs) are an evolutionarily conserved family of proteins with pivotal biological functions. Here we describe the cloning and functional characterization of a novel family member, human phosphatidylethanolamine-binding protein 4 (hPEBP4). hPEBP4 is expressed in most human tissues and highly expressed in tumor cells. Its expression in tumor cells is further enhanced upon tumor necrosis factor (TNF) α treatment, whereas hPEBP4 normally co-localizes with lysosomes, TNFα stimulation triggers its transfer to the cell membrane, where it binds to Raf-1 and MEK1. L929 cells overexpressing hPEBP4 are resistant to both TNFα-induced ERK1/2, MEK1, and JNK activation and TNFα-mediated apoptosis. Co-precipitation andin vitroprotein binding assay demonstrated that hPEBP4 interacts with Raf-1 and MEK1. A truncated form of hPEBP4, lacking the PE-binding domain, maintains lysosomal co-localization but has no effect on cellular responses to TNFα. Given that MCF-7 breast cancer cells expressed hPEBP4 at a high level, small interfering RNA was used to silence the expression of hPEBP4. We demonstrated that down-regulation of hPEBP4 expression sensitizes MCF-7 breast cancer cells to TNFα-induced apoptosis. hPEBP4 appears to promote cellular resistance to TNF-induced apoptosis by inhibiting activation of the Raf-1/MEK/ERK pathway, JNK, and PE externalization, and the conserved region of PE-binding domain appears to play a vital role in this biological activity of hPEBP4.
30
George-Alexander, Lou-Ella, Anna Kania, Sakeenah Hicks, Tian Mi, Christopher D. Scharer, and Jeremy Boss. "H3K9 dimethyltransferase G9a is an important epigenetic modulator of B cell differentiation." Journal of Immunology 204, no. 1_Supplement (May 1, 2020): 151.14. http://dx.doi.org/10.4049/jimmunol.204.supp.151.14.
Full textAbstract:
Abstract B cell differentiation is a tightly regulated process coordinated by the timed expression of various transcription factors and chromatin accessibility changes mediated by histone modifying enzymes. The histone methyltransferase (HMT) G9a, dimethylates histone H3 lysine 9 (H3K9) at promoters and inhibits gene expression via recruitment of proteins that impair chromatin accessibility. HMTs are expressed ubiquitously but display distinct enzymatic activities and patterns of chromosomal localization. During B cell differentiation, G9a was found to co-localize with Blimp-1 which is required to silence genes associated with a B cell phenotype and cellular proliferation. However, the B cell processes that are modulated by G9a mediated dimethylation remain to be elucidated. To assess the role of G9a in B-cell differentiation, we crossed G9afl/fl mice onto the CD19Cre/+ background (G9aKO mice). Stimulation of CD19Cre/+ (CreCtrl) and G9aKO mice with the T cell independent antigen LPS resulted in a significant increase of activated B cells and plasmablast in G9aKO mice. Further characterization of this phenotype, identified a skewing within the mature B cell population towards marginal zone (MZ) B cells in G9aKO mice. Regions with chromatin accessibility and expression changes identified by ATAC-Seq and RNA-Seq elucidated the B cell processes that are modulated in G9a deficient mice. B cell processes that are subject to direct modulation by G9a will be determined using CUT&RUN. Together, our data shows the importance of G9a in epigenetic modulation required for B cell function.
31
Bai, Xue, Liu-Lin Xiong, Chang-Le Fang, Hao-Li Zhou, Lu-Lu Xue, Yue Hu, Qing-Jie Xia, et al. "Interleukin 10 Plays an Important Role in Neonatal Rats with Hypoxic-Ischemia Associated with B-Cell Lymphoma 2 and Endoplasmic Reticulum Protein 29." Analytical Cellular Pathology 2021 (June 2, 2021): 1–12. http://dx.doi.org/10.1155/2021/6622713.
Full textAbstract:
Interleukin 10 (IL-10) is a synthetic inhibitor of human cytokines with immunomodulatory and anti-inflammatory effects. This study was designed to investigate the expression variation of IL-10 in the multiple sites including cortex, hippocampus, and lung tissues of neonatal hypoxic-ischemic (HI) rats and explore the crucial role of IL-10 in alleviating HI brain damage. In this study, neonatal Sprague-Dawley rats were subjected to the right common carotid artery ligation, followed by 2 h of hypoxia. The expression of IL-10 in the cortex, hippocampus, and lung tissues was measured with immunohistochemistry, real-time quantitative polymerase chain reaction (RT-qPCR), and western blot (WB). Immunofluorescence double staining was performed to observe the localization of IL-10 in neurons and astrocytes. Moreover, not-targeting and targeting IL-10 siRNA lentivirus vectors were injected into the rats of the negative control (NC) and IL-10 group, respectively, and the mRNA levels of B-cell lymphoma 2 (Bcl-2) and endoplasmic reticulum protein 29 (ERp29) were detected by RT-qPCR following IL-10 silence. The results demonstrated that the IL-10 expression was markedly increased after HI and IL-10 were colocalized with neurons and astrocytes which were badly injured by HI insult. In addition, Bcl-2 and ERp29 were remarkably decreased following IL-10 mRNA interference compared with the NC group. Our findings revealed that IL-10 exerted its antiapoptotic and neuroprotective effects by regulating the expression of Bcl-2 and ERp29, indicating that IL-10 may be a promising molecule target for HIE treatment.
32
Navarro, Angels, Ricardo E. Perez, Mo Rezaiekhaligh, Sherry M. Mabry, and Ikechukwu I. Ekekezie. "T1α/podoplanin is essential for capillary morphogenesis in lymphatic endothelial cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 295, no. 4 (October 2008): L543—L551. http://dx.doi.org/10.1152/ajplung.90262.2008.
Full textAbstract:
The lymphatic vasculature functions to maintain tissue perfusion homeostasis. Defects in its formation or disruption of the vessels result in lymphedema, the effective treatment of which is hampered by limited understanding of factors regulating lymph vessel formation. Mice lacking T1α/podoplanin, a lymphatic endothelial cell transmembrane protein, have malformed lymphatic vasculature with lymphedema at birth, but the molecular mechanism for this phenotype is unknown. Here, we show, using primary human lung microvascular lymphatic endothelial cells (HMVEC-LLy), that small interfering RNA-mediated silence of podoplanin gene expression has the dramatic effect of blocking capillary tube formation in Matrigel. In addition, localization of phosphorylated ezrin/radixin/moesin proteins to plasma membrane extensions, an early event in the capillary morphogenic program in lymphatic endothelial cells, is impaired. We find that cells with decreased podoplanin expression fail to properly activate the small GTPase RhoA early (by 30 min) after plating on Matrigel, and Rac1 shows a delay in its activation. Further indication that podoplanin action is linked to RhoA activation is that use of a cell-permeable inhibitor of Rho inhibited lymphatic endothelial capillary tube formation in the same manner as did podoplanin gene silencing, which was not mimicked by treatment with a Rac1 inhibitor. These data clearly demonstrate that early activation of RhoA in the lymphangiogenic process, which is required for the successful establishment of the capillary network, is dependent on podoplanin expression. To our knowledge, this is the first time that a mechanism has been suggested to explain the role of podoplanin in lymphangiogenesis.
33
Tuo, Hu, Baozhen Yao, Bing He, Shiqian Yu, Danni Li, Wenjing Li, and Lin Jin. "Silence of Insulin-Like Growth Factor 2 mRNA-Binding Protein 1 Prevents Vascular Smooth Muscle Cells Proliferation via Nuclear Factor of Activated T Cells Isoform-3/Ca2+/Calmodulin Pathway." Journal of Biomaterials and Tissue Engineering 11, no. 4 (April 1, 2021): 704–10. http://dx.doi.org/10.1166/jbt.2021.2747.
Full textAbstract:
Increased proliferation of vascular smooth muscle cells (VSMCs) contributes to the pathogenesis of atherosclerosis (AS), and the insulin like growth factor 2 (IGF2) is involved in AS through effects on VSMCs growth and migration. The IGF2 mRNA-binding protein 1(IGF2BP1) is a secreted protein that can bind to IGF2 and regulate its localization, however, whether IGF2BP1 could regulate VSMCs proliferation remains to be elucidated. This study aimed to investigate the role of IGF2BP1 in VSMCs proliferation and uncover the potential mechanism. Primary human aortic VSMCs that transfected with or without shRNA-IGF2BP1 were stimulated by platelet-derived growth factor-BB (PDGF-BB), and then cell proliferation, intracellular Ca2+ level, cell apoptosis and the expression of IGF2BP1, calmodulin (CaM) and cell cycle-related proteins were detected. RNA pull down assay was used to determine the interaction between IGF2BP1 and nuclear factor of activated T cells isoform-3 (NFATc3). We found that PDGF-BB promoted cell proliferation and enhanced IGF2BP1 protein expression in a concentration-dependent manner. The 10 μg/L PDGF-BB significantly increased intracellular Ca2+ level, NFATc3, CaM and calcineurin A protein expression, TUNEL-positive cells, and the expression of cell cycle-related proteins cyclin D1/E1/B1. However, knockdown of IGF2BP1 significantly blunted all these effects induced by PDGF-BB. In addition, IGF2BP1 could bind to NFATc3 RNA. Collectively, knockdown of IGF2BP1 could inhibit PDGFBB- induced VSMCs proliferation via targeting NFATc3/Ca2+/calmodulin pathway and disturbing the effect of NFATc3/ on cell cycle.
34
Wang, Taoyuan, Tiansheng Tang, Youguo Jiang, Tao He, Luyu Qi, Hongkai Chang, Yaya Qiao, et al. "PRIM2 Promotes Cell Cycle and Tumor Progression in p53-Mutant Lung Cancer." Cancers 14, no. 14 (July 11, 2022): 3370. http://dx.doi.org/10.3390/cancers14143370.
Full textAbstract:
p53 is a common tumor suppressor, and its mutation drives tumorigenesis. What is more, p53 mutations have also been reported to be indicative of poor prognosis in lung cancer, but the detailed mechanism has not been elucidated. In this study, we found that DNA primase subunit 2 (PRIM2) had a high expression level and associated with poor prognosis in lung cancer. Furthermore, we found that PRIM2 expression was abnormally increased in lung cancer cells with p53 mutation or altered the p53/RB pathway based on database. We also verified that PRIM2 expression was elevated by mutation or deletion of p53 in lung cancer cell lines. Lastly, silence p53 increased the expression of RPIM2. Thus, these data suggest that PRIM2 is a cancer-promoting factor which is regulated by the p53/RB pathway. The p53 tumor-suppressor gene integrates numerous signals that control cell proliferation, cell cycle, and cell death; and the p53/RB pathway determines the cellular localization of transcription factor E2F, which regulates the expression of downstream targets. Next, we explored the role of PRIM2 in lung cancer and found that knockdown of PRIM2 induced cell cycle arrest, increased DNA damage, and increased cell senescence, leading to decreased lung cancer cell proliferation. Lastly, the positive correlation between PRIM2 and E2F/CDK also indicated that PRIM2 was involved in promoting cell cycle mediated by p53/RB pathway. These results confirmed that the expression of PRIM2 is regulated by the p53/RB pathway in lung cancer cells, promotes DNA replication and mismatch repair, and activates the cell cycle. Overall, we found that frequent p53 mutations increased PRIM2 expression, activated the cell cycle, and promoted lung cancer progression.
35
Johnson, Morgan Brittany, Justin R. Halman, Daniel K. Miller, Joseph S. Cooper, Emil F. Khisamutdinov, Ian Marriott, and Kirill A. Afonin. "The immunorecognition, subcellular compartmentalization, and physicochemical properties of nucleic acid nanoparticles can be controlled by composition modification." Nucleic Acids Research 48, no. 20 (October 22, 2020): 11785–98. http://dx.doi.org/10.1093/nar/gkaa908.
Full textAbstract:
Abstract Nucleic acid nanoparticles (NANPs) have become powerful new platforms as therapeutic and diagnostic tools due to the innate biological ability of nucleic acids to identify target molecules or silence genes involved in disease pathways. However, the clinical application of NANPs has been limited by factors such as chemical instability, inefficient intracellular delivery, and the triggering of detrimental inflammatory responses following innate immune recognition of nucleic acids. Here, we have studied the effects of altering the chemical composition of a circumscribed panel of NANPs that share the same connectivity, shape, size, charge and sequences. We show that replacing RNA strands with either DNA or chemical analogs increases the enzymatic and thermodynamic stability of NANPs. Furthermore, we have found that such composition changes affect delivery efficiency and determine subcellular localization, effects that could permit the targeted delivery of NANP-based therapeutics and diagnostics. Importantly, we have determined that altering NANP composition can dictate the degree and mechanisms by which cell immune responses are initiated. While RNA NANPs trigger both TLR7 and RIG-I mediated cytokine and interferon production, DNA NANPs stimulate minimal immune activation. Importantly, incorporation of 2′F modifications abrogates RNA NANP activation of TLR7 but permits RIG-I dependent immune responses. Furthermore, 2′F modifications of DNA NANPs significantly enhances RIG-I mediated production of both proinflammatory cytokines and interferons. Collectively this indicates that off-target effects may be reduced and/or desirable immune responses evoked based upon NANPs modifications. Together, our studies show that NANP composition provides a simple way of controlling the immunostimulatory potential, and physicochemical and delivery characteristics, of such platforms.
36
Kim, William W. S., and Gerald Siu. "Subclass-Specific Nuclear Localization of a Novel Cd4 Silencer Binding Factor." Journal of Experimental Medicine 190, no. 2 (July 19, 1999): 281–92. http://dx.doi.org/10.1084/jem.190.2.281.
Full textAbstract:
The control of CD4 expression is essential for proper T lymphocyte development. We have previously described a cis-acting silencer element required for repressing transcription of the CD4 gene. Here we report the cloning and characterization of a novel factor that binds to a critical functional site in the CD4 silencer. This factor, referred to as silencer-associated factor (SAF), is a member of the helix-turn-helix factor family and shares sequence similarity with the homeodomain class of transcriptional regulators. Introduction of a specific mutation into the SAF binding site in the CD4 silencer abrogates silencer activity in transgenic mice, supporting the hypothesis that SAF is important in mediating silencer function. Although SAF is expressed in all lymphocytes, immunofluorescence studies indicate that SAF is present primarily in the cytoplasm in T cells in which the endogenous silencer is nonfunctional, whereas it is present primarily in the nucleus in T cells in which the silencer is functional. We thus hypothesize that the subclass-specific subcellular compartmentalization of SAF plays an important role in mediating the specificity of function of the CD4 silencer during T cell development.
37
Ma, Jun, Chuan Liu, Yuanqi Yang, Jie Yu, Jie Yang, Sanjiu Yu, Jihang Zhang, and Lan Huang. "C/EBPβ Acts Upstream of NF-κB P65 Subunit in Ox-LDL-Induced IL-1β Production by Macrophages." Cellular Physiology and Biochemistry 48, no. 4 (2018): 1605–15. http://dx.doi.org/10.1159/000492282.
Full textAbstract:
Background/Aims: Interleukin-1β (IL-1β) is one of the critical inflammatory factors during atherogenesis. CCAAT/enhancer binding proteins β (C/EBPβ), a regulator of IL-1β production, recently been evidenced as a key player in the development of atherosclerosis. However, the mechanisms of how C/EBPβ regulates the production of IL-1β are unclear. In this study, we aimed to explore the role of C/EBPβ in regulating IL-1β production in macrophages after oxidized low-density lipoprotein (ox-LDL) exposure and the underlying mechanisms. Methods: RAW264.7 macrophages were treated with 0, 25, 50 or 100 μg/ml ox-LDL for 12, 24 or 48 h. Small interfering RNAs were used to silence related proteins. The gene and protein expression levels were determined by quantitative real-time polymerase chain reaction or western blot (WB). IL-1β secretion was assessed by enzyme-linked immunosorbent assay. The cytoplasmic and nuclear proteins were evaluated by nuclear fractionation followed by WB. Localization of p65 was observed by immunofluorescence. The binding activity of p65 to IL-1β was tested by dual-luciferase reporter assay. Results: Ox-LDL increased IL-1β production, accompanied with increasing C/EBPβ and p65 expression in a dose- and time-dependent manner. Moreover, C/EBPβ deficiency in macrophages blocked ox-LDL-induced increases in IL-1β expression, maturation as well as p65 activation. However, p65 deficiency inhibited the increase in IL-1β production, but not C/EBPβ expression. Dual-luciferase reporter results showed that overexpression of C/EBPβ significantly enhanced binding activity of p65 to IL-1β promoter. In addition, C/EBP 1β deficiency in macrophages abolished the ox-LDL-induced gene transcription increases of IL-1β, IL-6, p65 and caspase-1. Conclusions: Our results demonstrate that C/EBPβ acts upstream of NF-κB p65 subunit in ox-LDL-induced IL-1β production in macrophages and may regulate IL-1β maturation by promoting caspase-1. C/EBPβ may be a promising candidate for the prevention and treatment of atherosclerosis.
38
Kirkland, Jacob G., and Rohinton T. Kamakaka. "Long-range heterochromatin association is mediated by silencing and double-strand DNA break repair proteins." Journal of Cell Biology 201, no. 6 (June 3, 2013): 809–26. http://dx.doi.org/10.1083/jcb.201211105.
Full textAbstract:
The eukaryotic genome is highly organized in the nucleus, and this organization affects various nuclear processes. However, the molecular details of higher-order organization of chromatin remain obscure. In the present study, we show that the Saccharomyces cerevisiae silenced loci HML and HMR cluster in three-dimensional space throughout the cell cycle and independently of the telomeres. Long-range HML–HMR interactions require the homologous recombination (HR) repair pathway and phosphorylated H2A (γ-H2A). γ-H2A is constitutively present at silenced loci in unperturbed cells, its localization requires heterochromatin, and it is restricted to the silenced domain by the transfer DNA boundary element. SMC proteins and Scc2 localize to the silenced domain, and Scc2 binding requires the presence of γ-H2A. These findings illustrate a novel pathway for heterochromatin organization and suggest a role for HR repair proteins in genomic organization.
39
Selech, Jaroslaw, Artūras Kilikevičius, Kristina Kilikevičienė, Sergejus Borodinas, Jonas Matijošius, Darius Vainorius, Jacek Marcinkiewicz, and Zaneta Staszak. "Force and Sound Pressure Sensors Used for Modeling the Impact of the Firearm with a Suppressor." Applied Sciences 10, no. 3 (February 2, 2020): 961. http://dx.doi.org/10.3390/app10030961.
Full textAbstract:
In this paper, a mathematical model for projectiles shooting in any direction based on sensors distributed stereoscopically is put forward. It is based on the characteristics of a shock wave around a supersonic projectile and acoustical localization. Wave equations for an acoustic monopole point source of a directed effect used for physical interpretation of pressure as an acoustic phenomenon. Simulation and measurements of novel versatile mechanical and acoustical damping system (silencer), which has both a muzzle break and silencer properties studied in this paper. The use of the proposed damping system can have great influence on the acoustic pressure field intensity from the shooter. A silencer regarded as an acoustic transducer and multi-holes waveguide with a chamber. Wave equations for an acoustic monopole point source of a directed effect used for the physical interpretation of pressure as an acoustic phenomenon. The numerical simulation results of the silencer with different configurations presented allow trends to be established. A measurement chain was used to compare the simulation results with the experimental ones. The modeling and experimental results showed an increase in silencer chamber volume results in a reduction of recorded pressure within the silencer chamber.
40
Antalis, TM, E. Costelloe, J. Muddiman, S. Ogbourne, and K. Donnan. "Regulation of the plasminogen activator inhibitor type-2 gene in monocytes: localization of an upstream transcriptional silencer." Blood 88, no. 10 (November 15, 1996): 3686–97. http://dx.doi.org/10.1182/blood.v88.10.3686.bloodjournal88103686.
Full textAbstract:
Transcriptional regulation of the plasminogen activator inhibitor type-2 (PAI-2) gene appears to be an important factor in the response of mononuclear phagocytes to inflammation. We have investigated here the molecular basis for PAI-2 synthesis in monocytic cells by reporter gene deletion analysis. A DNA fragment containing 5.1 kb of 5′ flanking region through to the start of the second exon was fused to a chloramphenicol acetyl transferase (CAT) reporter gene, transfected into macrophage and nonmacrophage cells and tested for PAI-2 promoter-directed CAT activity in the presence and absence of phorbol ester. Deletion analysis showed the existence of three major transcription regulatory regions. (1) A positive regulatory region contained in the proximal promoter mediates basal transcription and 12-phorbol 13-myristate acetate inducibility. (2) A negative regulatory region, or silencer, present between-1977 and-1675, was found to repress PAI-2 promoter activity in an orientation- and position-independent manner, but not in a cell-specific manner. (3) A second positive regulatory element, located upstream between approximately -5100 and -3300, appears to overcome inhibition mediated by the silencer in a cell- specific manner, suggesting a mechanism for the regulation of this gene. We have localized the motif responsible for silencer activity to a 28-bp DNA sequence containing a unique 12-bp palindrome centered at an Xba I restriction enzyme site, CTCTCTAGAGAG, which is designated the PAI-2-upstream silencer element-1 (PAUSE-1). This element binds a specific PAUSE-1 binding factor as determined by mobility shift analysis. We conclude that PAI-2 gene transcription is regulated by both positive and negative control mechanisms that may be important for the regulation of other genes as well.
41
Shimojo, Masahito, and Louis B. Hersh. "REST/NRSF-Interacting LIM Domain Protein, a Putative Nuclear Translocation Receptor." Molecular and Cellular Biology 23, no. 24 (December 15, 2003): 9025–31. http://dx.doi.org/10.1128/mcb.23.24.9025-9031.2003.
Full textAbstract:
ABSTRACT The transcriptional repressor REST/NRSF (RE-1 silencing transcription factor/neuron-restrictive silencer factor) and the transcriptional regulator REST4 share an N-terminal zinc finger domain structure involved in nuclear targeting. Using this domain as bait in a yeast two-hybrid screen, a novel protein that contains three LIM domains, putative nuclear localization sequences, protein kinase A phosphorylation sites, and a CAAX prenylation motif was isolated. This protein, which is localized around the nucleus, is involved in determining the nuclear localization of REST4 and REST/NRSF. We propose the name RILP, for REST/NRSF-interacting LIM domain protein, to label this novel protein. RILP appears to serve as a nuclear receptor for REST/NRSF, REST4, and possibly other transcription factors.
42
Xue, Qingming, Hong Jiang, Jinjie Wang, and Dongshan Wei. "LASP1 Induces Epithelial-Mesenchymal Transition in Lung Cancer through the TGF-β1/Smad/Snail Pathway." Canadian Respiratory Journal 2021 (December 6, 2021): 1–12. http://dx.doi.org/10.1155/2021/5277409.
Full textAbstract:
Background. LIM and SH3 domain protein 1 (LASP1), highly expressed in a variety of tumors, is considered as a novel tumor metastasis biomarker. However, it is unknown which signaling pathway works and how the signal transduces into cell nucleus to drive tumor progression by LASP1. The aim of this study is to explore the essential role of LASP1 in TGF-β1-induced epithelial-mesenchymal transition (EMT) in lung cancer cells. Methods. The gene and protein levels of LASP-1 were successfully silenced or overexpressed by LASP-1 shRNA lentivirus or pcDNA in TGF-β1-treated lung cancer cell lines, respectively. Then, the cells were developed EMT by TGF-β1. The cell abilities of invasion, migration, and proliferation were measured using Transwell invasion assay, wound healing assay, and MTT assay, respectively. Western blotting was used to observe the protein levels of EMT-associated molecules, including N-cadherin, vimentin, and E-cadherin, and the key molecules in the TGF-β1/Smad/Snail signaling pathway, including pSmad2 and Smad2, pSmad3 and Smad3, and Smad7 in cell lysates, as well as Snail1, pSmad2, and pSmad3 in the nucleus. Results. TGF-β1 induced higher LASP1 expression. LASP1 silence and overexpression blunted or promoted cell invasion, migration, and proliferation upon TGF-β1 stimulation. LASP1 also regulated the expression of vimentin, N-cadherin, and E-cadherin in TGF-β1-treated cells. Activity of key Smad proteins (pSmad2 and pSmad3) and protein level of Smad7 were markedly regulated through LASP1. Furthermore, LASP1 affected the nuclear localizations of pSmad2, pSmad3, and Snail1. Conclusion. This study reveals that LASP1 regulates the TGF-β1/Smad/Snail signaling pathway and EMT markers and features, involving in key signal molecules and their nuclear levels. Therefore, LASP1 might be a drug target in lung cancer.
43
Beier, Frank, Silvia Vornehm, Ernst Pöschl, Klaus von der Mark, and Mikko J. Lammi. "Localization of silencer and enhancer elements in the human type X collagen gene." Journal of Cellular Biochemistry 66, no. 2 (August 1, 1997): 210–18. http://dx.doi.org/10.1002/(sici)1097-4644(19970801)66:2<210::aid-jcb8>3.0.co;2-t.
Full text
44
Li, Jing, Si Chen, Run-Shuang Qiu, Li-Zhen Zhang, Yue Chen, Xue Zheng, Ting-Ting Li, Li-Hua Zhao, and Zhong-Kai Zhang. "Functional analysis of the nonstructural protein NSs of tomato zonate spot virus." PLOS ONE 17, no. 1 (January 24, 2022): e0262194. http://dx.doi.org/10.1371/journal.pone.0262194.
Full textAbstract:
Tomato zonate spot virus (TZSV), a member of the genus orthotospovirus, causes severe damage to vegetables and ornamental crops in southwest China. The NSs protein is an RNA silencing suppressor in various orthotospovirus like TZSV, but its mechanism and role in virus infection are poorly understood. Here, we observed that an NSs-GFP fusion protein was transiently expressed on the plasma membrane and Golgi bodies in Nicotiana benthamiana plants. The TZSV NSs gene was silenced and infiltrated into N. benthamiana and N. tabacum cv. K326. RT-qPCR and Indirect enzyme-linked immunosorbent assay (ID-ELISA) showed that the transcription and the protein expression of the NSs gene were inhibited by more than 90.00%, and the symptoms on silenced plants were alleviated. We also found that the expression of the Zingipain-2-like gene significantly decreased when the NSs gene was silenced, resulting in co-localization of the NSs-GFP and the Zingipain-2-like-mCherry fusion protein. The findings of this study provide new insights into the mechanism of silencing suppression by NSs, as well as its effect on systemic virus infection, and also support the theory of disease resistance breeding and control and prevention of TZSV in the field.
45
Perkins, Kelly J., Utpal Basu, Murat T. Budak, Caroline Ketterer, Santhosh M. Baby, Olga Lozynska, John A. Lunde, Bernard J. Jasmin, Neal A. Rubinstein, and Tejvir S. Khurana. "Ets-2 Repressor Factor Silences Extrasynaptic Utrophin by N-Box–mediated Repression in Skeletal Muscle." Molecular Biology of the Cell 18, no. 8 (August 2007): 2864–72. http://dx.doi.org/10.1091/mbc.e06-12-1069.
Full textAbstract:
Utrophin is the autosomal homologue of dystrophin, the protein product of the Duchenne's muscular dystrophy (DMD) locus. Utrophin expression is temporally and spatially regulated being developmentally down-regulated perinatally and enriched at neuromuscular junctions (NMJs) in adult muscle. Synaptic localization of utrophin occurs in part by heregulin-mediated extracellular signal-regulated kinase (ERK)-phosphorylation, leading to binding of GABPα/β to the N-box/EBS and activation of the major utrophin promoter-A expressed in myofibers. However, molecular mechanisms contributing to concurrent extrasynaptic silencing that must occur to achieve NMJ localization are unknown. We demonstrate that the Ets-2 repressor factor (ERF) represses extrasynaptic utrophin-A in muscle. Gel shift and chromatin immunoprecipitation studies demonstrated physical association of ERF with the utrophin-A promoter N-box/EBS site. ERF overexpression repressed utrophin-A promoter activity; conversely, small interfering RNA-mediated ERF knockdown enhanced promoter activity as well as endogenous utrophin mRNA levels in cultured muscle cells in vitro. Laser-capture microscopy of tibialis anterior NMJ and extrasynaptic transcriptomes and gene transfer studies provide spatial and direct evidence, respectively, for ERF-mediated utrophin repression in vivo. Together, these studies suggest “repressing repressors” as a potential strategy for achieving utrophin up-regulation in DMD, and they provide a model for utrophin-A regulation in muscle.
46
Froese, Natali, Michael Schwarzer, Ina Niedick, Ursula Frischmann, Mario Köster, Andrea Kröger, Peter P. Mueller, et al. "Innate Immune Responses in NF-κB-Repressing Factor-Deficient Mice." Molecular and Cellular Biology 26, no. 1 (January 1, 2006): 293–302. http://dx.doi.org/10.1128/mcb.26.1.293-302.2006.
Full textAbstract:
ABSTRACT NF-κB-repressing factor (NRF) is a transcriptional silencer protein that specifically counteracts the basal activity of several NF-κB-dependent promoters by direct binding to specific neighboring DNA sequences. In cell culture experiments, the reduction of NRF mRNA leads to a derepression of beta interferon, interleukin-8, and inducible nitric oxide synthase transcription. The X chromosome-located single-copy NRF gene is ubiquitously expressed and encodes a protein of 690 amino acids. The N-terminal part contains a nuclear localization signal, the DNA-binding domain, and the NF-κB-repressing domain, while the C-terminal part is responsible for double-stranded RNA binding and nucleolar localization. To study the function of NRF in a systemic context, transgenic mice lacking the NRF gene were created. Against predictions from in vitro experiments, mice with a deletion of the NRF gene are viable and have a phenotype that is indistinguishable from wild-type mice, even after challenge with different pathogens. The data hint towards an unexpected functional redundancy of NRF.
47
Wang, Jin, Feiyi Huang, Xiong You, and Xilin Hou. "Identification and Functional Characterization of a Cold-Related Protein, BcHHP5, in Pak-Choi (Brassica rapa ssp. chinensis)." International Journal of Molecular Sciences 20, no. 1 (December 26, 2018): 93. http://dx.doi.org/10.3390/ijms20010093.
Full textAbstract:
In plants, heptahelical proteins (HHPs) have been shown to respond to a variety of abiotic stresses, including cold stress. Up to the present, the regulation mechanism of HHP5 under low temperature stress remains unclear. In this study, BcHHP5 was isolated from Pak-choi (Brassica rapa ssp. chinensis cv. Suzhouqing). Sequence analysis and phylogenetic analysis indicated that BcHHP5 in Pak-choi is similar to AtHHP5 in Arabidopsis thaliana. Structure analysis showed that the structure of the BcHHP5 protein is relatively stable and highly conservative. Subcellular localization indicated that BcHHP5 was localized on the cell membrane and nuclear membrane. Furthermore, real-time quantitative polymerase chain reaction (RT-qPCR) analysis showed that BcHHP5 was induced to express by cold and other abiotic stresses. In Pak-choi, BcHHP5-silenced assay, inhibiting the action of endogenous BcHHP5, indicated that BcHHP5-silenced might have a negative effect on cold tolerance, which was further confirmed. All of these results indicate that BcHHP5 might play a role in abiotic response. This work can serve as a reference for the functional analysis of other cold-related proteins from Pak-choi in the future.
48
Overdijk, Elysa J. R., Vera Putker, Joep Smits, Han Tang, Klaas Bouwmeester, Francine Govers, and Tijs Ketelaar. "Phytophthora infestans RXLR effector AVR1 disturbs the growth of Physcomitrium patens without affecting Sec5 localization." PLOS ONE 16, no. 4 (April 8, 2021): e0249637. http://dx.doi.org/10.1371/journal.pone.0249637.
Full textAbstract:
Plant pathogens often exploit a whole range of effectors to facilitate infection. The RXLR effector AVR1 produced by the oomycete plant pathogen Phytophthora infestans suppresses host defense by targeting Sec5. Sec5 is a subunit of the exocyst, a protein complex that is important for mediating polarized exocytosis during plant development and defense against pathogens. The mechanism by which AVR1 manipulates Sec5 functioning is unknown. In this study, we analyzed the effect of AVR1 on Sec5 localization and functioning in the moss Physcomitrium patens. P. patens has four Sec5 homologs. Two (PpSec5b and PpSec5d) were found to interact with AVR1 in yeast-two-hybrid assays while none of the four showed a positive interaction with AVR1ΔT, a truncated version of AVR1. In P. patens lines carrying β-estradiol inducible AVR1 or AVR1ΔT transgenes, expression of AVR1 or AVR1ΔT caused defects in the development of caulonemal protonema cells and abnormal morphology of chloronema cells. Similar phenotypes were observed in Sec5- or Sec6-silenced P. patens lines, suggesting that both AVR1 and AVR1ΔT affect exocyst functioning in P. patens. With respect to Sec5 localization we found no differences between β-estradiol-treated and untreated transgenic AVR1 lines. Sec5 localizes at the plasma membrane in growing caulonema cells, also during pathogen attack, and its subcellular localization is the same, with or without AVR1 in the vicinity.
49
de Lucas, Susana, Joan Peredo, Rosa María Marión, Carmen Sánchez, and Juan Ortín. "Human Staufen1 Protein Interacts with Influenza Virus Ribonucleoproteins and Is Required for Efficient Virus Multiplication." Journal of Virology 84, no. 15 (May 26, 2010): 7603–12. http://dx.doi.org/10.1128/jvi.00504-10.
Full textAbstract:
ABSTRACT The influenza A virus genome consists of 8 negative-stranded RNA segments. NS1 is a nonstructural protein that participates in different steps of the virus infectious cycle, including transcription, replication, and morphogenesis, and acts as a virulence factor. Human Staufen1 (hStau1), a protein involved in the transport and regulated translation of cellular mRNAs, was previously identified as a NS1-interacting factor. To investigate the possible role of hStau1 in the influenza virus infection, we characterized the composition of hStau1-containing granules isolated from virus-infected cells. Viral NS1 protein and ribonucleoproteins (RNPs) were identified in these complexes by Western blotting, and viral mRNAs and viral RNAs (vRNAs) were detected by reverse transcription (RT)-PCR. Also, colocalization of hStau1 with NS1, nucleoprotein (NP), and PA in the cytosol of virus-infected cells was shown by immunofluorescence. To analyze the role of hStau1 in the infection, we downregulated its expression by gene silencing. Human HEK293T cells or A549 cells were silenced using either short hairpin RNAs (shRNAs) or small interfering RNAs (siRNAs) targeting four independent sites in the hStau1 mRNA. The yield of influenza virus was reduced 5 to 10 times in the various hStau1-silenced cells compared to that in control silenced cells. The expression levels of viral proteins and their nucleocytoplasmic localization were not affected upon hStau1 silencing, but virus particle production, as determined by purification of virions from supernatants, was reduced. These results indicate a role for hStau1 in late events of the influenza virus infection, possibly during virus morphogenesis.
50
Nakamura, Akira, Reiko Amikura, Kazuko Hanyu, and Satoru Kobayashi. "Me31B silences translation of oocyte-localizing RNAs through the formation of cytoplasmic RNP complex duringDrosophilaoogenesis." Development 128, no. 17 (September 1, 2001): 3233–42. http://dx.doi.org/10.1242/dev.128.17.3233.
Full textAbstract:
Embryonic patterning in Drosophila is regulated by maternal factors. Many such factors become localized as mRNAs within the oocyte during oogenesis and are translated in a spatio-temporally regulated manner. These processes are controlled by trans-acting proteins, which bind to the target RNAs to form a ribonucleoprotein (RNP) complex. We report that a DEAD-box protein, Me31B, forms a cytoplasmic RNP complex with oocyte-localizing RNAs and Exuperantia, a protein involved in RNA localization. During early oogenesis, loss of Me31B causes premature translation of oocyte-localizing RNAs within nurse cells, without affecting their transport to the oocyte. These results suggest that Me31B mediates translational silencing of RNAs during their transport to the oocyte. Our data provide evidence that RNA transport and translational control are linked through the assembly of RNP complex.