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ABSTRACT:
PROVIDER: PRJNA265045 | ENA |
REPOSITORIES: ENA
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Project description:Functions of BET proteins in GATA1-mediated transcription [ChIP-seq]
| PRJNA265060 | ENA
Project description:Functions of BET proteins in GATA1-mediated transcription [expression array]
| PRJNA264844 | ENA
Project description:Transcription factor GATA1 binding in erythroblasts in the presence and absence of BET inhibitor JQ1, and BET protein BRD3 and BRD4 binding in erythroblasts in the presence and absence of GATA1. Inhibitors of Bromodomain and Extra-Terminal motif proteins (BETs) are being evaluated for the treatment of cancer and other diseases yet their physiologic mechanisms remain largely unknown. We used genomic and genetic approaches to examine BET function in a hematopoietic maturation system driven by GATA1, an acetylated transcription factor previously shown to interact with BETs. We found that while BRD3 occupied the majority of GATA1 binding sites, BRD2 and BRD4 were also recruited to a subset of GATA1-occupied sites. Functionally, BET inhibition impaired GATA1-mediated transcriptional activation, but not repression, genome-wide. Co-activation by BETs was accomplished both by facilitating genomic occupancy of GATA1 and subsequently supporting transcription activation. Using a combination of CRISPR/CAS9-mediated genomic engineering and shRNA approaches we observed that depletion of either BRD2 or BRD4 alone blunted erythroid gene activation, while depletion of BRD3 only affected erythroid transcription in the setting of BRD2 deficiency. These results suggest that pharmacologic BET inhibition should be interpreted in the context of distinct steps in transcriptional activation and partially overlapping functions among BET family members. GATA1 null erythroblasts (G1E) conditionally expressing GATA1 as a GATA1-ER fusion protein were induced to express GATA1 by addition of 100nM estradiol for 24 hours. For GATA1 binding experiments this occurred in the absence or presence of 250nM JQ1. For BRD3 and BRD4 occupancy experiments G1E cells were compared to G1E cells with activated GATA1-ER fusion protein.
2015-02-23 | E-GEOD-62736 | biostudies-arrayexpress
Project description:Transcription factor GATA1 binding in erythroblasts in the presence and absence of BET inhibitor JQ1, and BET protein BRD3 and BRD4 binding in erythroblasts in the presence and absence of GATA1. Inhibitors of Bromodomain and Extra-Terminal motif proteins (BETs) are being evaluated for the treatment of cancer and other diseases yet their physiologic mechanisms remain largely unknown. We used genomic and genetic approaches to examine BET function in a hematopoietic maturation system driven by GATA1, an acetylated transcription factor previously shown to interact with BETs. We found that while BRD3 occupied the majority of GATA1 binding sites, BRD2 and BRD4 were also recruited to a subset of GATA1-occupied sites. Functionally, BET inhibition impaired GATA1-mediated transcriptional activation, but not repression, genome-wide. Co-activation by BETs was accomplished both by facilitating genomic occupancy of GATA1 and subsequently supporting transcription activation. Using a combination of CRISPR/CAS9-mediated genomic engineering and shRNA approaches we observed that depletion of either BRD2 or BRD4 alone blunted erythroid gene activation, while depletion of BRD3 only affected erythroid transcription in the setting of BRD2 deficiency. These results suggest that pharmacologic BET inhibition should be interpreted in the context of distinct steps in transcriptional activation and partially overlapping functions among BET family members.
2015-02-23 | GSE62736 | GEO
Project description:Role of the bromodomain and extraterminal motif (BET) protein BRD2 in CTCF chromatin occupancy, tested by CRISPR/Cas9-mediated depletion of BRD2 in GATA1-null erythroblasts expressing an inducible GATA1-ER fusion (G1E-ER4). Pharmacologic inhibitors of the BET (bromodomain and extraterminal motif) family of proteins are being explored for the treatment of various diseases, including cancer, yet the individual functions of BET proteins remain unclear. Here we find that BRD2 co-localizes with the architectural/insulator protein CCCTC-binding factor (CTCF) genome-wide. CTCF recruits BRD2 to co-bound sites, whereas BRD2 is dispensable for CTCF occupancy. Genome editing at a CTCF/BRD2 co-occupied site reveals a functional boundary element that upon perturbation results in transcriptional misregulation. Single-molecule RNA FISH reveals that either site-specific CTCF loss or BRD2 depletion increases the correlation in expression of two genes flanking the boundary. Together these findings indicate that BRD2 supports chromatin boundary activity in a CTCF-dependent manner and suggest that pharmacologic BET inhibitors influence gene expression in part by perturbing chromatin domain boundary function.
2017-03-31 | GSE80527 | GEO
Project description:Role of bromodomain and extra-terminal motif (BET) proteins in GATA1-null erythrolbasts (G1E) and in differentiation induced by activation of conditional GATA1 tested by addition of BET inhibitor JQ1 (250nM) Array protocols were conducted as described in the Ambion WT Expression Manual and the Affymetrix GeneChip Expression Analysis Technical Manual by the University of Pennsylvania Molecular Profiling Core. Two-factor design (+/- JQ1, +/- GATA1). External RNA spike-in controls (ERCC controls, Ambion) added to each sample in proportion to cell number at the time of RNA harvest.
2015-02-23 | E-GEOD-62709 | biostudies-arrayexpress
Project description:Role of bromodomain and extra-terminal motif (BET) proteins in GATA1-null erythrolbasts (G1E) and in differentiation induced by activation of conditional GATA1 tested by addition of BET inhibitor JQ1 (250nM) Array protocols were conducted as described in the Ambion WT Expression Manual and the Affymetrix GeneChip Expression Analysis Technical Manual by the University of Pennsylvania Molecular Profiling Core.
2015-02-23 | GSE62709 | GEO
Project description:Tissue-specific transcription patterns are preserved throughout cell divisions to maintain lineage fidelity. We investigated whether transcription factor GATA1 plays a role in transmitting hematopoietic gene expression programs through mitosis when transcription is transiently silenced. Live cell imaging revealed that a fraction of GATA1 is retained focally within mitotic chromatin. ChIP-seq of highly purified mitotic cells uncovered that key hematopoietic regulatory genes are occupied by GATA1 in mitosis. The GATA1 co- regulators FOG1 and TAL1 dissociate from mitotic chromatin, suggesting that GATA1 functions as platform for their postmitotic recruitment. Mitotic GATA1 target genes tend to re-activate more rapidly upon entry into G1 than genes from which GATA1 dissociates. A novel system designed to destroy GATA1 specifically during mitosis revealed that mitotic occupancy is required for rapid target gene reactivation. These studies suggest a requirement of mitotic “bookmarking” by GATA1 for the faithful propagation of cell type-specific transcription programs through cell division GATA1 occupancy profiles in mitotic G1E-ER4 +E2 cells generated by ChIP-sequencing. ChIP input DNA was sequenced as control. Previously reported (GSE18164) GATA1 occupancy in asynchrnous G1E-ER4 +E2 cells was analysed and compared with mitotic GATA1 occupancy.
2012-08-17 | E-GEOD-36589 | biostudies-arrayexpress
Project description:The complex relationship between Th1 and Th17 cells is incompletely understood. The transcription factor T-bet is best known as the master regulator of Th1 lineage commitment. However, attention is now focused on the repression of alternate T cell subsets mediated by T-bet, particularly the Th17 lineage. Specifically it has recently been suggested that pathogenic Th17 cells express T-bet and are dependent on IL-23. However, T-bet has previously been shown to be a negative regulator of Th17 cells. We have taken an unbiased approach to determine the functional impact of T-bet on Th17 lineage commitment. Genome-wide analysis of functional T-bet binding sites provides an improved understanding of the transcriptional regulation mediated by T-bet, and suggests novel mechanisms by which T-bet regulates T helper cell differentiation. Specifically, we show that T-bet negatively regulates Th17 lineage commitment via direct repression of the transcription factor interferon regulatory factor-4 (IRF4). An in vivo analysis of the pathogenicity of T-bet deficient T cells demonstrated that Th17 responses were augmented in the absence of T-bet, and we have defined a critical temporal window for T-bet function. The interaction of the two key transcription factors T-bet and IRF4 during the determination of T cell fate choice significantly advances our understanding of the mechanisms underlying the development of pathogenic T cells. ChIP-seq analysis of T-bet in WT and Tbet -/- mice.
2013-12-03 | E-GEOD-40623 | biostudies-arrayexpress
Project description:Interplays among lineage specific nuclear proteins, chromatin modifying enzymes and the basal transcription machinery govern cellular differentiation, but their dynamics of actions and coordination with transcriptional control are not fully understood. Alterations in chromatin structure appear to establish a permissive state for gene activation at some loci but they play an integral role in activation at other loci. To determine the predominant roles of chromatin states and factor occupancy in directing gene regulation during differentiation, we mapped chromatin accessibility, histone modifications, and nuclear factor occupancy genome-wide during mouse erythroid differentiation dependent on the master regulatory transcription factor GATA1. Remarkably, despite extensive changes in gene expression, the chromatin state profiles (proportions of a gene in a chromatin state dominated by activating or repressive histone modifications) and accessibility remain largely unchanged during GATA1-induced erythroid differentiation. In contrast, gene induction and repression are strongly associated with changes in patterns of transcription factor occupancy. Our results indicate that during erythroid differentiation, the broad features of chromatin states are established at the stage of lineage commitment, largely independently of GATA1. These determine permissiveness for expression, with subsequent induction or repression mediated by distinctive combinations of transcription factors. Using ChIP-Seq technology to examine DNase hypersensitivity, three transcription factors, and four histone modifications in Gata1-null murine G1E line and rescued G1E-ER4 subline, and also two of the transcription factors in mouse primary erythroblasts. ChIP input DNA was sequenced in each cell type as controls.
2011-07-05 | E-GEOD-30142 | biostudies-arrayexpress