Academic literature on the topic 'Chromodomain Helicase DNA binding 4 (CHD4)'

Chromodomain helicase DNA-binding protein 5 (CHD5) is localized exclusively in nucleus and forms nucleosome remodelling histone deacetylase (NuRD) complex with metastasis-associated protein (MTA)1/2, GATAD2A, histone deacetylase (HDAC)1/2, retinoblastoma-binding protein (RBBP)4/7 and methyl DNA-binding domain protein (MBD)3. Novel protein associations with CHD5–NuRD may account for the functional differences compared with CHD4–NuRD.

Pericentrin is an integral centrosomal component that anchors regulatory and structural molecules to centrosomes. In a yeast two-hybrid screen with pericentrin we identified chromodomain helicase DNA-binding protein 4 (CHD4/Mi2β). CHD4 is part of the multiprotein nucleosome remodeling deacetylase (NuRD) complex. We show that many NuRD components interacted with pericentrin by coimmunoprecipitation and that they localized to centrosomes and midbodies. Overexpression of the pericentrin-binding domain of CHD4 or another family member (CHD3) dissociated pericentrin from centrosomes. Depletion of CHD3, but not CHD4, by RNA interference dissociated pericentrin and γ-tubulin from centrosomes. Microtubule nucleation/organization, cell morphology, and nuclear centration were disrupted in CHD3-depleted cells. Spindles were disorganized, the majority showing a prometaphase-like configuration. Time-lapse imaging revealed mitotic failure before chromosome segregation and cytokinesis failure. We conclude that pericentrin forms complexes with CHD3 and CHD4, but a distinct CHD3–pericentrin complex is required for centrosomal anchoring of pericentrin/γ-tubulin and for centrosome integrity.

The chromatin remodeling factor chromodomain helicase DNA-binding protein 4 (CHD4) is a core component of the nucleosome remodeling and deacetylase (NuRD) complex. Due to its important role in DNA damage repair, CHD4 has been identified as a key determinant in cancer progression, stem cell differentiation, and T cell and B cell development. Accumulating evidence has revealed that CHD4 can function in NuRD dependent and independent manner in response to DNA damage. Mutations of CHD4 have been shown to diminish its functions, which indicates that interpretation of its mutations may provide tangible benefit for patients. The expression of CHD4 play a dual role in sensitizing cancer cells to chemotherapeutic agents, which provides new insights into the contribution of CHD4 to tumor biology and new therapeutic avenues.

Abstract Chromodomain Helicase DNA-binding protein 4 (CHD4, or Mi-2β) is a catalytic core subunit of Nucleosome Remodeling and Deacetylase (NuRD) complexes, which regulate chromatin structure and transcription in lymphocytes. CHD4 activities include ATP-dependent mobilization of nucleosomes, DNA binding and binding to histone tails. Here, we investigated requirements for CHD4 in B cell development in a mouse model system. We utilized Chd4flox/flox:Cd79a-Cre (Chd4 cko) mice, which inactivate Chd4 genes selectively in early B cell progenitors. These mice confirmed that CHD4 is essential for B lymphopoiesis. Following the loss of CHD4 expression, B cell development is arrested at the pro-B cell stage. Peripheral B220+ cells were nearly absent. To address the basis of the observed developmental arrest, we measured effects of the lack of CHD4 on proliferation and Igh gene rearrangements. CHD4-deficient pro-B cells fail to proliferate in response to IL-7. Furthermore, pro-B cells lacking CHD4 complete proximal VH to DJH rearrangements, but rearrange distal VH segments only rarely. Overall, our data demonstrate that CHD4 and NuRD complexes are essential for multiple aspects of early B cell development, including V(D)J recombination, proliferation and survival of pro-B cells.

The chromatin remodeler Chromodomain-helicase-DNA-binding protein 4 (CHD4) is crucial for the development of multiple organ systems. Functional mutations of CHD4 have recently been described in a developmental disorder, namely Siffrim-Hitz-Weiss syndrome (SIHIWES). Herein, we have generated a homozygous CHD4G1003D hESC line (WAe025-A-1) using CRISPR/eCas9-based gene editing in the WA-25 hESC line. The edited hESC line maintains normal karyotype, pluripotency, and ability to differentiate into three germ layers. This cell line will be a valuable resource for studying the functional role of CHD4 during the development and disease modeling of SIHIWES in vitro.

In response to ionizing radiation (IR), cells delay cell cycle progression and activate DNA repair. Both processes are vital for genome integrity, but the mechanisms involved in their coordination are not fully understood. In a mass spectrometry screen, we identified the adenosine triphosphate–dependent chromatin-remodeling protein CHD4 (chromodomain helicase DNA-binding protein 4) as a factor that becomes transiently immobilized on chromatin after IR. Knockdown of CHD4 triggers enhanced Cdc25A degradation and p21Cip1 accumulation, which lead to more pronounced cyclin-dependent kinase inhibition and extended cell cycle delay. At DNA double-strand breaks, depletion of CHD4 disrupts the chromatin response at the level of the RNF168 ubiquitin ligase, which in turn impairs local ubiquitylation and BRCA1 assembly. These cell cycle and chromatin defects are accompanied by elevated spontaneous and IR-induced DNA breakage, reduced efficiency of DNA repair, and decreased clonogenic survival. Thus, CHD4 emerges as a novel genome caretaker and a factor that facilitates both checkpoint signaling and repair events after DNA damage.

Abstract Gata3 is a GATA family transcription factor that controls differentiation of naïve CD4 T cells into T helper (Th) 2 cells. However, it is unknown how Gata3 simultaneously activates Th2-specific genes while repressing those of other Th lineages. Here we show that Chd4 (chromodomain helicase DNA-binding protein 4) forms a complex with Gata3 in Th2 cells that both activates Th2 cytokine transcription and represses the Th1 cytokine IFNγ. We define a Gata3/Chd4/p300 transcriptional activation complex at the Th2 cytokine loci and a Gata3/Chd4-NuRD repression complex at the Tbx21 locus in Th2 cells. We also demonstrated a physiological role for Chd4 in Th2-dependent inflammation in an in vivo model of asthmatic inflammation. Thus, Gata3/Chd4 forms functionally distinct complexes, which mediate both positive and negative gene regulation to facilitate Th2 cell differentiation.

Cell lineage specification is a tightly regulated process that is dependent on appropriate expression of lineage and developmental stage-specific transcriptional programs. Here, we show that Chromodomain Helicase DNA-binding protein 4 (CHD4), a major ATPase/helicase subunit of Nucleosome Remodeling and Deacetylase Complexes (NuRD) in lymphocytes, is essential for specification of the early B cell lineage transcriptional program. In the absence of CHD4 in B cell progenitors in vivo, development of these cells is arrested at an early pro-B-like stage that is unresponsive to IL-7 receptor signaling and unable to efficiently complete V(D)J rearrangements at Igh loci. Our studies confirm that chromatin accessibility and transcription of thousands of gene loci are controlled dynamically by CHD4 during early B cell development. Strikingly, CHD4-deficient pro-B cells express transcripts of many non-B cell lineage genes, including genes that are characteristic of other hematopoietic lineages, neuronal cells, and the CNS, lung, pancreas, and other cell types. We conclude that CHD4 inhibits inappropriate transcription in pro-B cells. Together, our data demonstrate the importance of CHD4 in establishing and maintaining an appropriate transcriptome in early B lymphopoiesis via chromatin accessibility.

The CHD4 (chromodomain-helicase-DNA-binding 4) (or Mi-2β) protein is a founding component of the NuRD (nucleosome remodelling and deacetylation) complex. NuRD has long been known to function in transcriptional regulation, and is conserved throughout the animal and plant kingdoms. In recent years, evidence has steadily accumulated indicating that CHD4 can both function outside of the NuRD complex and also play important roles in cellular processes other than transcriptional regulation. A number of loss-of-function studies have identified important roles for CHD4 in the DNA-damage response and in cell cycle progression through S-phase and into G2. Furthermore, as part of NuRD, it participates in regulating acetylation levels of p53, thereby indirectly regulating the G1/S cell cycle checkpoint. Although CHD4 has a somewhat complicated relationship with the cell cycle, recent evidence indicates that CHD4 may exert some tumour-suppressor functions in human carcinogenesis. CHD4 is a defining member of the NuRD complex, but evidence is accumulating that CHD4 also plays important NuRD-independent roles in the DNA-damage response and cell cycle progression, as well as in transcriptional regulation.

Cells respond to ionizing radiation (IR)–induced DNA double-strand breaks (DSBs) by orchestrating events that coordinate cell cycle progression and DNA repair. How cells signal and repair DSBs is not yet fully understood. A genome-wide RNA interference screen in Caenorhabditis elegans identified egr-1 as a factor that protects worm cells against IR. The human homologue of egr-1, MTA2 (metastasis-associated protein 2), is a subunit of the nucleosome-remodeling and histone deacetylation (NuRD) chromatin-remodeling complex. We show that knockdown of MTA2 and CHD4 (chromodomain helicase DNA-binding protein 4), the catalytic subunit (adenosine triphosphatase [ATPase]) of NuRD, leads to accumulation of spontaneous DNA damage and increased IR sensitivity. MTA2 and CHD4 accumulate in DSB-containing chromatin tracks generated by laser microirradiation. Directly at DSBs, CHD4 stimulates RNF8/RNF168-dependent formation of ubiquitin conjugates to facilitate the accrual of RNF168 and BRCA1. Finally, we show that CHD4 promotes DSB repair and checkpoint activation in response to IR. Thus, the NuRD chromatin–remodeling complex is a novel regulator of DNA damage responses that orchestrates proper signaling and repair of DSBs.

In eukaryotic cells, genomic DNA is organized into small units called nucleosomes, each of which generally consists of a histone octamer and DNA wrapping around this histone core, so that the whole genome can be efficiently packed into a small nucleus. On the other hand, the presence of nucleosome remodelers ensures the genetic information still remains accessible to regulatory factors. Although it was known for a long time that these remodellers can weaken the interaction between the DNA and histones in an ATP-dependent manner to expose part of the DNA sequence, the underlying mechanisms have not been fully explored, especially for the CHD remodeler family. In the project, we assembled recombinant nucleosomes and used them as the substrate to test the remodelling ability of CHD4 and also NuRD (Nucleosome Remodelling Deacetylase) complex, using single molecule FRET (fluorescence resonance energy transfer) experiments. The FRET experiment involves fluorescent labelling of one of the histones and also of the DNA, which allows the monitoring of the translocation of the nucleosome in real time. Other experimental approaches, including real-time remodelling rate monitoring, and gel-based remodelling assays were also carried out. Together with structural studies, these experiments were used to delineate the biochemical mechanism of remodelling by CHD4-family chromatin remodelling proteins.

La radiothérapie métabolique à l'iode radioactif est la pierre angulaire du traitement des métastases à distance des cancers différenciés de la thyroïde. Cette thérapie est basée sur l'expression à la membrane basale des thyrocytes du transporteur de l'iode appelé NIS pour « Natrium Iodide Symporter ». La mutation BRAFV600E est présente dans 45 à 60 % des cancers papillaires de la thyroïde qui représentent 80% des cancers thyroïdiens. La présence de cette mutation est associée aux tumeurs thyroïdiennes les plus agressives avec un faible niveau ou une absence d'expression du NIS. La perte de la captation d'iode radioactif se traduit par la résistance à la radiothérapie métabolique constituant un enjeu majeur pour le traitement des patients atteints de ce cancer. L'une des approches pour le traitement des patients réfractaires à la radiothérapie métabolique consiste à augmenter l'absorption de l'iode.Au niveau transcriptionnel, notre équipe a déjà montré, à travers une analyse comparative qui porte sur environ 500 PTCs de la base de données TCGA, que NOX4 est fortement exprimée dans les PTCs-BRAFV600E comparativement aux PTCs-BRAFwt. Néanmoins, au niveau protéique, aucun lien n'a été établie entre la mutation BRAFV600E et NOX4 dans les tumeurs malignes et non malignes (BRAFV600E/BRAFwt). Dans mon projet de thèse, nous illustrons pour la première fois une corrélation positive entre la présence de la mutation BRAFV600E et la surexpression de la protéine NOX4 dans les tissus tumoraux PTCs. La surexpression de NOX4 est associée au caractère agressif des tumeurs. De plus, nous avons montré que 60% des C-PTCs infiltrant surexpriment NOX4 indépendamment du statut mutationnel de BRAF, ce qui suggère que NOX4 pourrait être considérée comme un co-marqueur potentiel de l'agressivité des PTCs. De manière intéressante la protéine NOX4 était également surexprimée dans les maladies thyroïdiennes non malignes (les Basedow, goitres et hyperplasies) avec différentes localisations subcellulaires, suggérant un rôle de NOX4 dans la progression vers la malignité thyroïdienne.Par ailleurs, sur le plan mécanistique, notre équipe a précédemment montré que BRAFV600E contrôle l'expression de NOX4 sous l'effet de TGF-β /SMAD3 et que les ERO dérivées de NOX4 contribuent à la répression du NIS. L'inhibition de NOX4 favorise la réactivation du NIS. Cette réversibilité suggère une contribution à un mécanisme épigénétique. CHD4, une sous-unité du complexe du remodelage NuRD, joue un rôle important dans la répression des gènes. Elle est fortement exprimée dans les PTCs dans lequel elle est associée à un mauvais pronostic. Dans cette étude, nous avons montré que la voie TGF-β/SMAD3 régule l'expression de la protéine CHD4. Cette dernière coopère avec les DNMTs dans la répression du NIS dans plusieurs lignées thyroïdiennes tumorales mutées pour BRAFV600E. Par ailleurs, nous montrons que CHD4 répond aux dommages oxydatifs à l'ADN induites par les ERO dérivés de NOX4. En effet, l'inhibition de NOX4 ou de son partenaire fonctionnel p22phox, induit une diminution du recrutement de CHD4 à la chromatine. Ce recrutement est dépendant d'OGG1 et MSH6, deux protéines impliquées dans la réparation des dommages oxydatifs à l'ADN. Cette étude identifie CHD4 en tant que nouvelle cible thérapeutique dans les tumeurs thyroïdiennes réfractaires à la radiothérapie métabolique
Metabolic radiotherapy with radioiodine is the cornerstone of the treatment of distant metastases of differentiated thyroid cancers. This therapy depends on the expression at the basal membrane of thyrocytes of the Natrium Iodide Symporter 'NIS'. BRAFV600E mutation is present in 45 to 60% of papillary thyroid carcinomas, which represent 80% of thyroid cancers. The presence of this mutation is associated with the most aggressive thyroid tumors with low levels or absence of NIS expression. The loss of radioactive iodine uptake translates into resistance to metabolic radiotherapy, constituting a major issue for the treatment of patients with this cancer. One approach for treating patients refractory to metabolic radiotherapy is to increase iodine uptake.At the transcriptional level, our team has already shown, through a comparative analysis concerning approximately 500 PTCs from the TCGA database, that NOX4 was strongly expressed in PTCs-BRAFV600E compared to PTCs-BRAFwt. However, at the protein level, no link has been established between the BRAFV600E mutation and NOX4 in malignant and non-malignant tumors (BRAFV600E/BRAFwt). In my thesis project, we illustrate for the first time a positive correlation between the presence of BRAFV600E mutation and the overexpression of NOX4 protein in PTC tumor tissues. The overexpression of NOX4 was associated with an aggressive nature of tumors. Furthermore, we showed that 60% of infiltrating C-PTCs overexpress NOX4 independently of BRAF mutational status, suggesting that NOX4 could be considered as a potential co-marker of PTC aggressiveness. Interestingly, NOX4 protein was also overexpressed in non-malignant thyroid diseases (Basedow, goiters, and hyperplasias), with different subcellular localizations, suggesting a role for NOX4 in progression to thyroid malignancy.Furthermore, on a mechanistic level, our team has previously shown that BRAFV600E controls the expression of NOX4 under the effect of TGF-β/SMAD3 and that NOX4-derived ROS contribute to the repression of NIS. Inhibition of NOX4 promotes reactivation of the NIS. This reversibility suggests a contribution to an epigenetic mechanism. CHD4, a subunit of the NuRD remodeling complex, plays an essential role in gene repression. it was found to be strongly expressed in PTCs, in which it was associated with a poor prognosis. In this study, we showed that the TGF-β/SMAD3 pathway regulates the expression of CHD4 protein. The latter cooperates with DNMTs in repressing NIS in several thyroid tumor cells lines mutated for BRAFV600E. Furthermore, we showed that CHD4 responds to oxidative DNA damage induced by NOX4-derived ROS. Indeed, inhibition of NOX4 or its functional partner p22phox reduces the recruitment of CHD4 to chromatin. This recruitment depends on OGG1 and MSH6, two proteins involved in oxidative DNA damage repair. This study identifies CHD4 as a new therapeutic candidate in radioiodine-refractory thyroid cancers