Bromodomain Containing Protein 4 (BRD4) Regulates Inducible Expression Of Its Interactome In The Innate Response To Respiratory Syncytial Virus
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PROVIDER: PRJNA743332 | ENA |
REPOSITORIES: ENA
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Project description:We examine the effect of a selective BRD4 inhibitor n the epithelial response to RSV infection. Wild type human small airway epithelial cells were infected in the absence or prescend of ZL0454. 24 h later, RNA was extracted and subjected to short read illumina RNA Seq.
2021-10-01 | GSE179353 | GEO
Project description:Transcriptional elongation by RNA polymerase II (Pol II) is regulated by positive transcription elongation factor b (P-TEFb) in association with Bromodomain-containing protein 4 (BRD4). We used genome-wide chromatin immunoprecipitation sequencing in primary human CD4+ T cells to reveal that BRD4 co-localizes with Ser2-phosphorylated Pol II (Pol II Ser2) at both enhancers and promoters of active genes. Disruption of bromodomain:histone acetylation interactions by JQ1, a small-molecule bromodomain inhibitor, resulted in decreased BRD4 binding, reduced Pol II Ser2, and reduced expression of lineage-specific genes in primary human CD4+ T cells. A large number of JQ1-disrupted BRD4 binding regions exhibited di-acetylated H4 (lysine-5 and -8) and H3K27 acetylation (H3K27ac), which correlated with the presence of histone acetyltransferases and deacetylases. Genes associated with BRD4/H3K27ac co-occupancy exhibited significantly higher activity than those associated with H3K27ac or BRD4 binding alone. Comparison of BRD4 binding in T cells and in human embryonic stem cells revealed that enhancer BRD4 binding sites were predominantly lineage-specific. Our findings suggest that BRD4-driven Pol II phosphorylation at serine 2 plays an important role in regulating lineage-specific gene transcription in human CD4+ T cells. Examination of BRD4, total Pol II, serine 2 phosphorylated Pol II and serine 5 phosphorylated Pol II binding in CD4+ T cells (with and without JQ1 treatment) and BRD4 binding in human embryonic stems cell; PolyA RNA expression in CD4+ T cells( with and without JQ1 treatment) using RNA-seq
2012-11-14 | E-GEOD-33281 | biostudies-arrayexpress
Project description:Transcriptional elongation by RNA polymerase II (Pol II) is regulated by positive transcription elongation factor b (P-TEFb) in association with Bromodomain-containing protein 4 (BRD4). We used genome-wide chromatin immunoprecipitation sequencing in primary human CD4+ T cells to reveal that BRD4 co-localizes with Ser2-phosphorylated Pol II (Pol II Ser2) at both enhancers and promoters of active genes. Disruption of bromodomain:histone acetylation interactions by JQ1, a small-molecule bromodomain inhibitor, resulted in decreased BRD4 binding, reduced Pol II Ser2, and reduced expression of lineage-specific genes in primary human CD4+ T cells. A large number of JQ1-disrupted BRD4 binding regions exhibited di-acetylated H4 (lysine-5 and -8) and H3K27 acetylation (H3K27ac), which correlated with the presence of histone acetyltransferases and deacetylases. Genes associated with BRD4/H3K27ac co-occupancy exhibited significantly higher activity than those associated with H3K27ac or BRD4 binding alone. Comparison of BRD4 binding in T cells and in human embryonic stem cells revealed that enhancer BRD4 binding sites were predominantly lineage-specific. Our findings suggest that BRD4-driven Pol II phosphorylation at serine 2 plays an important role in regulating lineage-specific gene transcription in human CD4+ T cells.
2012-11-14 | GSE33281 | GEO
Project description:Respiratory Syncytial Virus (RSV) causes severe inflammation and airway pathology in children and the elderly by infecting the epithelial cells of the upper and lower respiratory tract. RSV replication is sensed by intracellular pattern recognition receptors upstream of the IRF and NF-$\upkappa$B transcription factors. These proteins coordinate an innate inflammatory response via Bromodomain containing protein 4 (BRD4), a protein that functions as a scaffold for unknown transcriptional regulators. To better understand the pleiotropic regulatory function of BRD4, we examine the BRD4 interactome and identify how RSV infection dynamically alters it. To accomplish these goals, we leverage native immunoprecipitation and Parallel Accumulation – Serial Fragmentation (PASEF) mass spectrometry to examine BRD4 complexes isolated from human alveolar epithelial cells in the absence or presence of RSV infection. In addition, we explore the role of BRD4's acetyl-lysine binding bromodomains in mediating these interactions by using a highly selective competitive bromodomain inhibitor. We identify 101 proteins that are significantly enriched in the BRD4 complex and are responsive to both RSV-infection and BRD4 inhibition. These proteins are highly enriched in transcription factors and transcriptional coactivators. Among them, we identify members of the AP1 transcription factor complex, a complex important in innate signaling and cell stress responses. We independently confirm the BRD4/AP1 interaction in primary human small airway epithelial cells. We conclude that BRD4 recruits multiple transcription factors during RSV infection in a manner dependent on acetyl-lysine binding domain interactions. This data suggests that BRD4 recruits transcription factors to target its RNA processing complex to regulate gene expression in innate immunity and inflammation.
2021-03-17 | PXD023983 | Pride
Project description:During heat stress cyto-protective genes including heat shock proteins are transcriptionally up-regulated and post-transcriptional splicing is inhibited. In contrast, co-transcriptional mRNA-splicing is maintained. These factors closely resemble the proteotoxic stress response during tumor development. The bromodomain protein BRD4 has been identified as an integral member of the oxidative stress as well as of the inflammatory response. Furthermore, there is evidence for BRD4's role in splicing regulation; Using RNA-Seq analyses we indeed found a significant increase in splicing inhibition, in particular intron retentions, during heat treatment in BRD4-deficient cells, but not under normal conditions. Subsequent experiments revealed that heat stress leads to the recruitment of BRD4 to nuclear stress bodies, to the interaction with the heat shock factor 1 (HSF1) and to the transcriptional up-regulation of non-coding Sat III RNA transcripts. These findings implicate BRD4 as a central regulator of splicing during heat stress. Since BRD4 is a potent target for anti-cancer therapies, our data linking BRD4 to the splicing machinery and the heat stress response - give additional insight into the mode of action of BRD4 inhibitors. WI38 cells have been treated by heatshock and anti BRD4 siRNA and combination.
2016-09-07 | E-GEOD-73471 | biostudies-arrayexpress
Project description:Bromodomain-containing protein 4 (BRD4) is an important epigenetic reader which promotes gene transcription to modulate cell-specific functions and is under intensive investigation for its potential as an anti-tumor therapeutic target. However, the role of BRD4 in non-transformed cells remains unclear. Here we demonstrate that BRD4 is required for the expression of epithelial-specific genes and suppression of stem cell-like properties by binding to the distal regions of epithelial-related genes. Moreover, BRD4 occupancy correlates with enhancer activity and enhancer RNA (eRNA) transcription of epithelial differentiation-specific genes. Interestingly, we show that BRD4 perturbation regulates the expression of Grainy Head-like transcription factor, GRHL3, whose depletion partially mimics BRD4 inhibition and blocks differentiated phenotype. By binding to the distal regions of GRHL3, BRD4 promotes RNA polymerase-II occupancy and thus affects eRNA transcription. Altogether, these findings provide evidence that BRD4 promotes a differentiated epithelial phenotype in non-transformed mammary cells at least in part through the activation of GRHL3 expression.
2016-10-06 | GSE72932 | GEO
Project description:Bromodomain-containing protein 4 (BRD4) is an important epigenetic reader which promotes gene transcription to modulate cell-specific functions and is under intensive investigation for its potential as an anti-tumor therapeutic target. However, the role of BRD4 in non-transformed cells remains unclear. Here we demonstrate that BRD4 is required for the expression of epithelial-specific genes and suppression of stem cell-like properties by binding to the distal regions of epithelial-related genes. Moreover, BRD4 occupancy correlates with enhancer activity and enhancer RNA (eRNA) transcription of epithelial differentiation-specific genes. Interestingly, we show that BRD4 perturbation regulates the expression of Grainy Head-like transcription factor, GRHL3, whose depletion partially mimics BRD4 inhibition and blocks differentiated phenotype. By binding to the distal regions of GRHL3, BRD4 promotes RNA polymerase-II occupancy and thus affects eRNA transcription. Altogether, these findings provide evidence that BRD4 promotes a differentiated epithelial phenotype in non-transformed mammary cells at least in part through the activation of GRHL3 expression.
2016-10-06 | GSE72931 | GEO
Project description:DNA damage activates a complex signaling network in cells that blocks cell cycle progression, recruits factors involved in DNA repair, and/or triggers programs that control senescence or programmed cell death. Alterations in chromatin structure are known to be important for the initiation and propagation of the DNA damage response, although the molecular details are unclear. We investigated the role of chromatin structure in the DNA damage response by monitoring multiple timedependent checkpoint signaling and response events with a high-content multiplex image-based RNAi screen of chromatin modifying and interacting genes. We discovered that Brd4, a double bromodomain-containing protein, functions as an endogenous inhibitor of DNA damage signaling by binding to acetylated histones at sites of open chromatin and altering chromatin accessibility. Loss of Brd4 or disruption of acetyl-lysine binding results in an increase in both the number and size of radiation-induced !H2AX nuclear foci while overexpression of a Brd4 splice isoform completely suppresses !H2AX formation, despite equivalent double strand break formation. Brd4 knock-down cells displayed altered chromatin structure, prolonged cell cycle checkpoint arrest and enhanced survival after irradiation, while overexpression of Brd4 isoform B results in enhanced radiationinduced lethality. Brd4 is the target of the t(15;19) chromosomal translocation in a rare form of cancer, NUT Midline Carcinoma. Acetyl lysine-bromodomain interactions of the Brd4-NUT fusion protein suppresses !H2AX foci in discrete nuclear compartments, rendering cells more radiosensitive, mimicking overexpression of Brd4 isoform B. NUT Midline Carcinoma is sensitive to radiotherapy, however tumor material from this rare cancer is scarce. We therefore investigated Brd4 expression in another human cancer commonly treated with radiotherapy, glioblastoma multiforme, and found that expression of Brd4 isoform B correlated specifically with treatment response to radiotherapy. These data implicate Brd4 as an endogenous insulator of DNA damage signaling through recognition of epigenetic modifications in chromatin and suggest that expression of the Brd4 in human cancer can modulate the clinical response to DNA-damaging cancer therapy. Two replicates each of U2OS cells expressing either Brd4 shRNA or a control shRNA
2013-07-14 | E-GEOD-30700 | biostudies-arrayexpress
Project description:To study the role of the bromodomain (BD) in BRD4-dependent gene expression, we compared the function of wild type BRD4 and a mutant BRD4-mBD, which carries a point mutation in each of the two BDs. We first knocked down endogenous BRD4 by shRNA (shBRD4) and then stably reconstituted the cells with shBRD4-resistant YFP-BRD4 (wild type or mBD mutant). Following BRD4 reconstitution, the degree of recovery in gene expression was analyzed by Affymetrix Mouse Exon 1.0 ST array. Wild-type BRD4 restored gene expression significantly and far more efficiently than the mBD mutant.
2014-11-10 | GSE56370 | GEO
Project description:The BET family protein BRD4, which forms the CDK9-containing BRD4-PTEFb complex, is considered to be a master regulator of RNA polymerase II (Pol II) pause release. Because its tandem bromodomains interact with acetylated histone lysine residues, it has long been thought that BRD4 requires these bromodomains for its recruitment to chromatin and transcriptional regulatory function. Here, using rapid depletion and genetic complementation with domain deletion mutants, we demonstrate that BRD4 bromodomains are dispensable for Pol II pause release. A minimal, bromodomain-less C-terminal BRD4 fragment containing the PTEFb-interacting C-terminal motif (CTM) is instead both necessary and sufficient to mediate Pol II pause release in the absence of full-length BRD4. Although BRD4-PTEFb can associate with chromatin through acetyl recognition, our results indicate that a distinct, active BRD4-PTEFb population functions to regulate transcription independently of bromodomain-mediated chromatin association. These findings may enable more effective pharmaceutical modulation of BRD4-PTEFb activity.
2023-07-14 | GSE232869 | GEO