Epigenetic regulation by BAF (mSWI/SNF) complexes limits neural stem cell proliferation by suppressing Wnt signaling in late cortical neurogenesis
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA417717 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR6277000.fastq.gz | Fastqsanger.gz | |||
| SRR6277010.fastq.gz | Fastqsanger.gz | |||
| SRR6277020.fastq.gz | Fastqsanger.gz | |||
| SRR6277030.fastq.gz | Fastqsanger.gz | |||
| SRR6277001.fastq.gz | Fastqsanger.gz |
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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:We have analyzed changes in gene expression, histone 3 lysine 4 dimethyl (H3K4me2) and histone 3 lysine 37 trimethyl (H3K27me3) levels in the embryonic cortex at E17.5 resulting from conditional deletion of BAF complex - i.e., double knockout of BAF155 and BAF170, in late cortical progenitors utilizing Cre expression under human GFAP (hGFAP) promoter (dcKO_hGFAP-Cre). Moreover, we also analyzed gene expression in WT E17.5 cortex treated with vehicle and Wnt inhibitor together with that of in dcKO_hGFAP-Cre cortex treated with Wnt inhibitor. Gene expression studies were conducted by RNA-Seq and histone marks were analyzed by ChIP-Seq.
2018-04-22 | GSE106711 | GEO
Project description:We report RNA-Seq from the cortex of mouse brain at P3 comparing wild types to those with conditional knockout (cKO) of BAF (mSWI/SNF) using Cre-loxP system. The Cre recombinase is expessed under GFAP promoter.
2021-01-22 | GSE165228 | GEO
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.
2013-03-30 | GSE45625 | GEO
Project description:The mammalian SWI/SNF (mSWI/SNF) family of chromatin remodelers govern cell type-specific chromatin accessibility and gene expression and assemble as three distinct complexes: canonical BAF (cBAF), Polybromo-associated BAF (PBAF), and non-canonical BAF (ncBAF). ARID1A and ARID1B are paralog subunits that specifically nucleate the assembly of cBAF complexes and are frequently dual deleted in highly aggressive differentiated endometrial carcinomas (DECs). Here, in cellular models and primary human tumors, we find that ARID1A/B-mediated cBAF loss results in increased ncBAF and PBAF biochemical abundance and function genome-wide to maintain the DEC oncogenic signature. Further, treatment of ARID1A/1B-mutant cell lines and PDX models in vivo with a clinical-grade SMARCA4/2 ATPase inhibitor, FHD-286, markedly attenuates cell proliferation and tumor growth, and synergizes with carboplatin-based chemotherapy. Taken together, these findings reveal the oncogenic contributions of shifted of mSWI/SNF family complex abundance and chromatin-level gene regulatory functions and suggest therapeutic utility of mSWI/SNF complex small molecule inhibitors in dedifferentiated endometrial carcinoma and other cBAF-disrupted cancer types.
2025-08-07 | PXD058236 | Pride
Project description:Rhabdomyosarcoma (RMS) is a highly malignant pediatric cancer of skeletal muscle lineage. The aggressive alveolar subtype is commonly characterized by t(2;13) or t(1;13) translocations with the expression of PAX3- or PAX7-FOXO1 fusion transcription factors respectively and is known as fusion positive RMS (FP-RMS). FP-RMS tumors rely on the fusion gene to maintain their proliferative state while avoiding terminal differentiation program. Since disruptions of normal development are likely governed by epigenetic changes in these low-mutational-burden tumors, we investigated the contributions of chromatin regulatory complexes to RMS tumor maintenance. We demonstrate the essentiality of the mSWI/SNF ATPase BRG1 for FP-RMS proliferation and discover that RMS significantly overexpress SMARCA4 (encoding BRG1) compared to skeletal muscle. We define the mSWI/SNF subunit repertoire in FP-RMS and provide evidence for the assembly of multiple mSWI/SNF complexes including canonical BAF, PBAF and non-canonical (nc)BAF in FP-RMS. Proteomic studies suggest proximity between PAX3-FOXO1 and BAF complexes, which was further supported by genome-wide binding profiles revealing enhancer colocalization of BAF with FP-RMS core regulatory transcription factors. We report that mSWI/SNF complexes act as sensors of chromatin state, which are recruited to sites of de novo histone acetylation. Phenotypically, interference with mSWI/SNF complex function induces transcriptional activation of the skeletal muscle differentiation program associated with MYCN enhancer invasion at myogenic target genes. Finally, BRG1 targeting compounds reproduce the effects of genetic ablation. We conclude that inhibition of BRG1 overcomes the differentiation blockade of FP-RMS cells and may provide a therapeutic strategy for treating this lethal childhood tumor.
2020-11-20 | MSV000086494 | MassIVE
Project description:Rhabdomyosarcoma (RMS) is a highly malignant pediatric cancer of skeletal muscle lineage. The aggressive alveolar subtype is commonly characterized by t(2;13) or t(1;13) translocations with the expression of PAX3- or PAX7-FOXO1 fusion transcription factors respectively and is known as fusion positive RMS (FP-RMS). FP-RMS tumors rely on the fusion gene to maintain their proliferative state while avoiding terminal differentiation program. Since disruptions of normal development are likely governed by epigenetic changes in these low-mutational-burden tumors, we investigated the contributions of chromatin regulatory complexes to RMS tumor maintenance. We demonstrate the essentiality of the mSWI/SNF ATPase BRG1 for FP-RMS proliferation and discover that RMS significantly overexpress SMARCA4 (encoding BRG1) compared to skeletal muscle. We define the mSWI/SNF subunit repertoire in FP-RMS and provide evidence for the assembly of multiple mSWI/SNF complexes including canonical BAF, PBAF and non-canonical (nc)BAF in FP-RMS. Proteomic studies suggest proximity between PAX3-FOXO1 and BAF complexes, which was further supported by genome-wide binding profiles revealing enhancer colocalization of BAF with FP-RMS core regulatory transcription factors. We report that mSWI/SNF complexes act as sensors of chromatin state, which are recruited to sites of de novo histone acetylation. Phenotypically, interference with mSWI/SNF complex function induces transcriptional activation of the skeletal muscle differentiation program associated with MYCN enhancer invasion at myogenic target genes. Finally, BRG1 targeting compounds reproduce the effects of genetic ablation. We conclude that inhibition of BRG1 overcomes the differentiation blockade of FP-RMS cells and may provide a therapeutic strategy for treating this lethal childhood tumor.
2021-04-01 | GSE162052 | GEO
Project description:Mammalian SWI/SNF (mSWI/SNF) ATP-dependent chromatin remodeling complexes are large, multisubunit molecular machines that play vital roles in regulating genomic architecture and are frequently disrupted in human cancer and developmental disorders. To date, the organization and pathway of assembly of these chromatin regulators remain unknown, presenting a major barrier to structural and functional determination. Here we elucidate the architecture and assembly pathway of three different classes of mammalian SWI/SNF complexes: canonical BAF, PBAF, and a newly defined complex, ncBAF, and define the requirement of each subunit for complex formation and stability. Using affinity purification of endogenous complexes from mammalian and Drosophila cells coupled with cross linking-mass spectrometry, we uncover three distinct and evolutionarily conserved modules, their organization, and the temporal incorporation of these modules into each complete mSWI/SNF complex class.
2018-10-18 | PXD010123 | Pride
Project description:Neurogenesis is a key developmental event through which neurons are generated from neural stem/progenitor cells. Chromatin remodeling BAF (mSWI/SNF) complexes have been reported to play essential roles in the neurogenesis of the central nervous system. However, whether BAF complexes are required for neuron generation in the olfactory system is unknown. Here, we identified onscBAF and ornBAF complexes, which are specifically present in olfactory neural stem cells (oNSCs) and olfactory receptor neurons (ORNs), respectively. We demonstrated that BAF155 subunit is highly expressed in both oNSCs and ORNs, whereas high expression of BAF170 subunit is observed only in ORNs. We report that conditional deletion of BAF155, a core subunit in both onscBAF and ornBAF complexes, causes impaired proliferation of oNSCs as well as defective maturation and axonogenesis of ORNs in the developing olfactory epithelium (OE), while the high expression of BAF170 is important for maturation of ORNs. Interestingly, in the absence of BAF complexes in BAF155/BAF170 double-conditional knockout mice (dcKO), OE is not specified. Mechanistically, BAF complex is required for normal activation of Pax6-dependent transcriptional activity in stem cells/progenitors of the OE. Our findings unveil a novel mechanism mediated by the mSWI/SNF complex in OE neurogenesis and development.
| S-EPMC5017785 | biostudies-literature
Project description:The mammalian SWI/SNF (mSWI/SNF) family of chromatin remodelers govern cell type-specific chromatin accessibility and gene expression and assemble as three distinct complexes: canonical BAF (cBAF), Polybromo-associated BAF (PBAF), and non-canonical BAF (ncBAF). ARID1A and ARID1B are paralog subunits that specifically nucleate the assembly of cBAF complexes and are frequently dual deleted in highly aggressive differentiated endometrial carcinomas (DECs). Here, in cellular models and primary human tumors, we find that ARID1A/B-mediated cBAF loss results in increased ncBAF and PBAF biochemical abundance and function genome-wide to maintain the DEC oncogenic signature. Further, treatment of ARID1A/1B-mutant cell lines and PDX models in vivo with a clinical-grade SMARCA4/2 ATPase inhibitor, FHD-286, markedly attenuates cell proliferation and tumor growth, and synergizes with carboplatin-based chemotherapy. Taken together, these findings reveal the oncogenic contributions of shifted of mSWI/SNF family complex abundance and chromatin-level gene regulatory functions and suggest therapeutic utility of mSWI/SNF complex small molecule inhibitors in dedifferentiated endometrial carcinoma and other cBAF-disrupted cancer types.
2025-08-04 | GSE283800 | GEO