Transcriptional effects of dominant-negative G784E Smarca4 mutation in mouse embryonic stem cells [RNA-seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE98469 | GEO | 2017/10/22
SECONDARY ACCESSION(S): PRJNA385176
REPOSITORIES: GEO
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Project description:We investigated the chromatin effects of a Smarca4 ATPase mutant observed in primary tumors and cancer cell lines. Compared to cells expressing only wild-type Smarca4, heterozygous expression of G784E Smarca4 mutant led to reduction of H3K27ac and RNAP at a set of enhancer sites.
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Project description:We generated a library of Smarca4 variants with mutations in conserved regions of the N-terminal ATPase domain based on mutants observed in primary tumors and cancer cell lines. Heterozygous expression of Smarca4 ATPase mutants led to decreased accessibility at active enhancers in mouse embryonic stem cells.
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Project description:Mammalian SWI/SNF complexes are multi-subunit chromatin remodeling complexes associated with an ATPase, either SMARCA4 or SMARCA2. Heterozygous mutations in the SMARCA2 ATPase cause Nicolaides-Baraitser Syndrome (NCBRS), an intellectual disability syndrome associated with delayed speech onset. We engineered human embryonic stem cells (hESCs) to carry NCBRS-associated heterozygous SMARCA2 K755R or R1159Q mutations. While SMARCA2 mutant hESCs were phenotypically normal, differentiation to neural progenitors cells (NPCs) was severely impaired. We find that SMARCA2 mutations cause enhancer reorganization with loss of SOX3-dependent neural enhancers and prominent emergence of astrocyte-specific de novo enhancers. Changes in chromatin accessibility at enhancers were associated with an increase in SMARCA2 binding and retargeting of SMARCA4. We show that AP-1 family member FRA2 is aberrantly overexpressed in SMARCA2 mutant NPCs, where it functions as a pioneer factor at de novo enhancers. Together, our results demonstrate SMARCA2 mutations cause impaired differentiation through enhancer reprogramming via inappropriate targeting of SMARCA4.
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Project description:SMARCA2 and SMARCA4 are two mutually exclusive ATPase subunits of SWI/SNF complex. SMARCA4 deficient lung cancer population selectively depend on SMARCA2 for cancer growth phenotype. Rescue experiments with ectopic expression of wild-type, bromodomain mutant and ATPase dead SMARCA2 and SMARCA4 highlight that ATPase domain is the drug target. In this study, we performed genome-wide microarray and differential gene expression profiling on isogenic lung cancer lines expressing cDNA rescue constructs for wild-type, bromodomain mutant and ATPase dead SMARCA2 and SMARCA4
2015-07-21 | GSE69088 | GEO
Project description:The packaging of DNA into chromatin plays an important role in transcriptional regulation and nuclear processes. Brahma related gene-1 SMARCA4 (also known as BRG1), the essential ATPase subunit of the mammalian SWI/SNF chromatin remodeling complex, uses the energy from ATP hydrolysis to disrupt nucleosomes at target regions. Although the transcriptional role of SMARCA4 at gene promoters is well-studied, less is known about its role in higher-order genome organization. SMARCA4 knockdown in human mammary epithelial MCF-10A cells resulted in 176 up-regulated genes, including many related to lipid and calcium metabolism, and 1292 down-regulated genes, some of which encode extracellular matrix (ECM) components that can exert mechanical forces and affect nuclear structure. ChIP-seq analysis of SMARCA4 localization and SMARCA4-bound super-enhancers demonstrated extensive binding at intergenic regions. Furthermore, Hi-C analysis showed extensive SMARCA4-mediated alterations in higher-order genome organization at multiple resolutions. First, SMARCA4 knockdown resulted in clustering of intra- and inter- sub-telomeric regions, demonstrating a novel role for SMARCA4 in telomere organization. SMARCA4 binding was enriched at TAD (Topologically Associating Domain) boundaries, and SMARCA4 knockdown resulted in weakening of TAD boundary strength. Taken together, these findings provide a dynamic view of SMARCA4-dependent changes in higher-order chromatin organization and gene expression, identifying SMARCA4 as a novel component of chromatin organization. Hi-C and RNA-seq experiments were conducted in MCF-10A shSCRAM and shSMARCA4 cells. SMARCA4 ChIP-seq was conducted in wildtype MCF-10A cells.
2016-06-02 | E-GEOD-74716 | biostudies-arrayexpress
Project description:Mutations in SMARCA4, a central ATPase of the human BAF/PBAF chromatin remodeling complexes, cause developmental abnormalities and promote cancer development. The pathogenic effects of SMARCA4 loss are often linked to the de-regulation of a relatively small number of key target genes. Here, to understand how chromatin remodeling by SMARCA4 results in specific transcriptional perturbations, we used genome engineering to correct a homozygous mutation in SMARCA4 in the well-characterized lung adenocarcinoma A549 cell line and profiled changes in SMARCA2/4 occupancy, chromatin accessibility, histone marks and transcription. Restoration of SMARCA4 causes a dramatic increase in chromatin accessibility at low affinity TF binding sites. Despite the widespread increase in chromatin accessibility, we observe comparatively attenuated changes in gene expression. Although there is a marked correlation between the number of local activated DHSs and the transcriptional responsivity of a gene, the influence of distal DHSs appears modified by a gene's promoter architecture and domain-scale chromatin organization. The largest changes in expression occur for genes in isolated, SMARCA4 sensitive chromatin domains that undergo region-wide chromatin remodeling upon reintroduction of SMARCA4. Our results reveal that interactions between distal enhancers, genome organization, and promoter architecture add transcriptional specificity to the global chromatin effects of BAF/PBAF complex perturbation and target the response to key developmental pathways.
2020-05-20 | GSE132292 | GEO
Project description:Mutations in SMARCA4, a central ATPase of the human BAF/PBAF chromatin remodeling complexes, cause developmental abnormalities and promote cancer development. The pathogenic effects of SMARCA4 loss are often linked to the de-regulation of a relatively small number of key target genes. Here, to understand how chromatin remodeling by SMARCA4 results in specific transcriptional perturbations, we used genome engineering to correct a homozygous mutation in SMARCA4 in the well-characterized lung adenocarcinoma A549 cell line and profiled changes in SMARCA2/4 occupancy, chromatin accessibility, histone marks and transcription. Restoration of SMARCA4 causes a dramatic increase in chromatin accessibility at low affinity TF binding sites. Despite the widespread increase in chromatin accessibility, we observe comparatively attenuated changes in gene expression. Although there is a marked correlation between the number of local activated DHSs and the transcriptional responsivity of a gene, the influence of distal DHSs appears modified by a gene's promoter architecture and domain-scale chromatin organization. The largest changes in expression occur for genes in isolated, SMARCA4 sensitive chromatin domains that undergo region-wide chromatin remodeling upon reintroduction of SMARCA4. Our results reveal that interactions between distal enhancers, genome organization, and promoter architecture add transcriptional specificity to the global chromatin effects of BAF/PBAF complex perturbation and target the response to key developmental pathways.
2020-05-20 | GSE132291 | GEO
Project description:Mutations in SMARCA4, a central ATPase of the human BAF/PBAF chromatin remodeling complexes, cause developmental abnormalities and promote cancer development. The pathogenic effects of SMARCA4 loss are often linked to the de-regulation of a relatively small number of key target genes. Here, to understand how chromatin remodeling by SMARCA4 results in specific transcriptional perturbations, we used genome engineering to correct a homozygous mutation in SMARCA4 in the well-characterized lung adenocarcinoma A549 cell line and profiled changes in SMARCA2/4 occupancy, chromatin accessibility, histone marks and transcription. Restoration of SMARCA4 causes a dramatic increase in chromatin accessibility at low affinity TF binding sites. Despite the widespread increase in chromatin accessibility, we observe comparatively attenuated changes in gene expression. Although there is a marked correlation between the number of local activated DHSs and the transcriptional responsivity of a gene, the influence of distal DHSs appears modified by a gene's promoter architecture and domain-scale chromatin organization. The largest changes in expression occur for genes in isolated, SMARCA4 sensitive chromatin domains that undergo region-wide chromatin remodeling upon reintroduction of SMARCA4. Our results reveal that interactions between distal enhancers, genome organization, and promoter architecture add transcriptional specificity to the global chromatin effects of BAF/PBAF complex perturbation and target the response to key developmental pathways.
2020-05-20 | GSE132290 | GEO
Project description:Genomic and proteomic analyses coupled withmechanistic studies identified TGFBR2as a direct transcriptional target of SOX4and demonstrated that TGFBR2 is required to mediate SOX4-dependent PI3K signaling. We further reportthat SOX4 and the SWI/SNF ATPase SMARCA4, which are uniformly overexpressed in basal-like tumors,form a previously unreported complex that is requiredto maintain an open chromatin conformationat the TGFBR2regulatory regionsin order tomediateTGFBR2expressionand PI3K signaling.
2021-03-01 | GSE158295 | GEO
Project description:Dysregulation of PI3K/Akt signaling is a dominant feature in basal-like or triple-negative breast cancers (TNBC). However, the mechanisms regulating this pathway are largely unknown in this subset of aggressive tumors. Here we demonstrate that the transcription factor SOX4 is a key regulator of PI3K signaling in TNBC. Genomic and proteomic analyses coupled with mechanistic studies identified TGFBR2 as a direct transcriptional target of SOX4 and demonstrated that TGFBR2 is required to mediate SOX4-dependent PI3K signaling. We further report that SOX4 and the SWI/SNF ATPase SMARCA4, which are uniformly overexpressed in basal-like tumors, form a previously unreported complex that is required to maintain an open chromatin conformation at the TGFBR2 regulatory regions in order to mediate TGFBR2 expression and PI3K signaling. Collectively, our findings delineate the mechanism by which SOX4 and SMARCA4 cooperatively regulate PI3K/Akt signaling and suggest that this complex may play an essential role in TNBC genesis and/or progression. Kinase enrichment proteomic analysis was performed using HCC1143 breast cancer cells treated with a control siRNA pool or a pool targeting SOX4 in biological triplicate to evaluate the effects on the functional kinome.
2021-03-03 | PXD022596 | Pride