BAF250a regulates nucleosome occupancy and histone modification in priming embryonic stem cell differentiation
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE59082 | GEO | 2015/08/03
SECONDARY ACCESSION(S): PRJNA254343
REPOSITORIES: GEO
Similar Datasets
Project description:BAF complex is one major group of chromatin remodeling factors in mammals. However, how BAF regulated nucleosomes and other histone modifications is not clear. Here we delete BAF250a, a major component in esBAF to study the nucleosome and histone changes in ESCs. We find that deletion of BAF250a leads to nucleosome occupancy increase in TSS regions and non-pioneer transcription factor binding sites. BAF250a deletion also cause overall decrease of H3K27me3 modification. Collectively, these results reveals how BAF complex coordinates nucleosome, histone modification to control ESC function. Sample 1-4: Nucleosome profiles in WT and BAF250a KO ESCs. Sample 5-10: profiling of H3K4me3 and H3K27me3 in WT and BAF250 KO ESCs.
2015-08-03 | E-GEOD-59082 | biostudies-arrayexpress
Project description:BAF250a regulates nucleosome occupancy and histone modification in priming embryonic stem cell differentiation
| PRJNA254343 | ENA
Project description:BAF and PBAF are mammalian SWI/SNF family chromatin remodeling complexes that possess multiple histone/DNA-binding subunits and create nucleosome-depleted/free regions for transcription activation. Despite previous structural studies and recent advance of SWI/SNF family complexes, it remains incompletely understood how PBAF-nucleosome complex is organized. Here we determined structure of 13-subunit human PBAF in complex with acetylated nucleosome in ADP-BeF3-bound state. Four PBAF-specific subunits work together with nine BAF/PBAF-shared subunits to generate PBAF-specific modular organization, distinct from that of BAF at various regions. PBAF-nucleosome structure reveals six histone-binding domains and four DNA-binding domains/modules, the majority of which directly bind histone/DNA. This multivalent nucleosome-binding pattern, not observed in previous studies, suggests that PBAF may integrate comprehensive chromatin information to target genomic loci for function. Our study reveals molecular organization of subunits and histone/DNA-binding domains/modules in PBAF-nucleosome complex and provides structural insights into PBAF-mediated nucleosome association complimentary to the recently reported PBAF-nucleosome structure.
2023-03-11 | PXD036708 | Pride
Project description:Recent exon sequencing studies of human tumors have revealed that subunits of mSWI/SNF or BAF complexes are mutated in more than 20% of human malignancies, yet the mechanisms involved in tumor suppression is unclear. BAF chromatin remodeling complexes are polymorphic assemblies that use energy provided by ATP hydrolysis to regulate transcription through the control of chromatin structure and the placement of Polycomb (PcG) across the genome. Several proteins dedicated to this large multi-subunit complex, including SMARCA4 (BRG1) and BAF250A (ARID1A), are mutated at frequencies similar to that of many recognized tumor suppressors. In particular, the core ATPase BRG1 is mutated in 5-10% of childhood medulloblastoma (MB) and greater than 15% of Burkitt's Lymphoma (BL). Here we find a novel function of BAF complexes in decatenating newly replicated sister chromatids, which is necessary for proper chromosome segregation during mitosis. We find that deletion of Brg1, as well as the expression of Brg1 point mutants identified in human tumors leads to anaphase bridge formation (sister chromatids linked by catenated strands of DNA), and a G2/M phase block characteristic of the decatenation checkpoint. Endogenous BAF complexes directly interact with endogenous TopoIIα through BAF250a and are required for TopoIIα binding to about 12,000 sites over the genome. Our results indicate that TopoIIα’s chromatin binding is dependent on the ATPase activity of Brg1, which is compromised in oncogenic Brg1 mutants. These studies indicate that the ability of TopoIIα to prevent DNA entanglement at mitosis requires BAF complexes and suggest that this activity contributes to the role of BAF subunits as tumor suppressors. Examination of sites of TopoIIa activity in WT and Brg1-/- ES cells as defined by TopoIIa-DNA covalent adducts formed in the presence of etoposide
2013-03-30 | E-GEOD-45625 | biostudies-arrayexpress
Project description:Functional interactions between gene regulatory factors and chromatin architecture have been difficult to directly assess. Here, we use micrococcal nuclease (MNase) footprinting to probe the functions of two chromatin remodeling complexes. By simultaneously quantifying alterations in small MNase footprints over the binding sites of 30 regulatory factors in mouse embryonic stem cells (ESCs), we provide evidence that esBAF and Mbd3/NuRD modulate the binding of several regulatory proteins. In addition, we find that nucleosome occupancy is reduced at specific loci in favor of subnucleosomes upon depletion of esBAF, including sites of histone H2A.Z localization. Consistent with these data, we demonstrate that esBAF is required for normal H2A.Z localization in ESCs, suggesting esBAF either stabilizes H2A.Z-containing nucleosomes or promotes subnucleosome to nucleosome conversion by facilitating H2A.Z deposition. Therefore, integrative examination of MNase footprints reveals insights into nucleosome dynamics and functional interactions between chromatin structure and key gene regulatory factors. Examine three read size footprints from MNase-Seq in EGFP KD, Mbd3 KD, and Smarca4 KD mESCs using ChIP-Seq datasets.
2015-08-27 | E-GEOD-68400 | biostudies-arrayexpress
Project description:Functional interactions between gene regulatory factors and chromatin architecture have been difficult to directly assess. Here, we use micrococcal nuclease (MNase) footprinting to probe the functions of two chromatin remodeling complexes. By simultaneously quantifying alterations in small MNase footprints over the binding sites of 30 regulatory factors in mouse embryonic stem cells (ESCs), we provide evidence that esBAF and Mbd3/NuRD modulate the binding of several regulatory proteins. In addition, we find that nucleosome occupancy is reduced at specific loci in favor of subnucleosomes upon depletion of esBAF, including sites of histone H2A.Z localization. Consistent with these data, we demonstrate that esBAF is required for normal H2A.Z localization in ESCs, suggesting esBAF either stabilizes H2A.Z-containing nucleosomes or promotes subnucleosome to nucleosome conversion by facilitating H2A.Z deposition. Therefore, integrative examination of MNase footprints reveals insights into nucleosome dynamics and functional interactions between chromatin structure and key gene regulatory factors.
2015-08-27 | GSE68400 | GEO
Project description:The mammalian BRG1-associated factors (BAF) complex is a multi-subunit chromatin remodeling complex that is an important component of the embryonic stem cell (ESC) transcriptional regulatory network. However, the role of individual subunits in BAF complex targeting and function needs to be elucidated. Here, we find that the Bromodomain containing protein 9 (BRD9) defines a smaller, non-canonical BAF complex in mouse ESCs that is distinct from the canonical embryonic stem cell BAF (esBAF) and the polybromo-associated BAF (PBAF) complexes. This BRD9-containing BAF complex, or BBAF complex, uniquely incorporates the BRD4-interacting chromatin remodeling associated protein-like (BICRAL) or its paralog BICRA and lacks several esBAF subunits including BAF47, ARID1A and BAF57. We demonstrate that BBAF and esBAF complexes are targeted to different features of the genome and are co-bound with different sets of pluripotency transcription factors. Specifically, BBAF complexes co-localize with key regulators of naïve pluripotency, KLF4 and Sp5, on the genome. Consistent with this, we provide evidence that BBAF’s specific function is to regulate the transcription of genes involved in the maintenance of naïve pluripotency, including Nanog and Prdm14. Additionally, we show that BRD9 is displaced from chromatin by the selective BRD9 bromodomain inhibitor, I-BRD9, and that this leads to changes in target gene expression. Together, our results provide evidence for the identification of a new BAF complex, and demonstrate functionally specific roles for BAF complex assemblies in maintaining the transcriptional network of pluripotency.
2018-10-18 | PXD010670 | Pride
Project description:Approximately 75% of the human genome is transcribed, the majority of which does not encode protein. However, most noncoding RNA (ncRNA) is rapidly degraded after transcription, and relatively few have established functions, questioning the significance of this observation. Here we show that esBAF, a SWI/SNF family nucleosome remodeling factor, suppresses transcription of ncRNAs from approximately 57,000 nucleosome-depleted regions (NDRs) throughout the genome of mouse embryonic stem cells (ESCs). We show that esBAF functions both to keep NDRs nucleosome-free and to promote elevated nucleosome occupancy adjacent to NDRs. Reduction of adjacent nucleosome occupancy upon esBAF depletion is strongly correlated with ncRNA expression, suggesting that flanking nucleosomes form a barrier to pervasive transcription. Upon forcing nucleosome occupancy near an NDR using a nucleosome-positioning sequence, we find that esBAF is no longer required to silence transcription. These data reveal a novel role for esBAF in suppressing pervasive transcription from open chromatin regions in ESCs.
2015-02-12 | GSE57170 | GEO
Project description:Approximately 75% of the human genome is transcribed, the majority of which does not encode protein. However, most noncoding RNA (ncRNA) is rapidly degraded after transcription, and relatively few have established functions, questioning the significance of this observation. Here we show that esBAF, a SWI/SNF family nucleosome remodeling factor, suppresses transcription of ncRNAs from approximately 57,000 nucleosome-depleted regions (NDRs) throughout the genome of mouse embryonic stem cells (ESCs). We show that esBAF functions both to keep NDRs nucleosome-free and to promote elevated nucleosome occupancy adjacent to NDRs. Reduction of adjacent nucleosome occupancy upon esBAF depletion is strongly correlated with ncRNA expression, suggesting that flanking nucleosomes form a barrier to pervasive transcription. Upon forcing nucleosome occupancy near an NDR using a nucleosome-positioning sequence, we find that esBAF is no longer required to silence transcription. These data reveal a novel role for esBAF in suppressing pervasive transcription from open chromatin regions in ESCs. Examine nucleosome occupancy (MNase-Seq) and transcript production (CapSeq and RNA-Seq) in EGFP KD and Smarca4 KD ESCs
2015-02-12 | E-GEOD-57170 | biostudies-arrayexpress
Project description:Using ChIP-seq technology, we aimed to provide insight into the consequences of the knockdown of Smarcb1, an essential esBAF subunit, for the binding of the esBAF complex (Smarca4), the PRC2 complex (Ezh2) as well as for histone marks H3K27me3, H3K27ac and H3K4me3. We show that Smarcb1 knockdown results in the change of BAF complex binding in both directions: decreased binding (potentially by loss of function) as well as increased binding (potentially by retargeting). Furthermore, we see that binding changes especially occur in regions important for basic cellular functions (adhesion, cell organization, metabolism) as well as regions crucial for development (especially nervous system development). In addition, we depicted binding changes in enhancer regions in which a decrease of BAF binding was much more prominent than in gene regions.
2022-04-27 | GSE186667 | GEO