The SAS-Chromatin Remodeling Complex Mediates Inflorecence-Specific Chromatin Accessibility for Transcription Factor Binding
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE254656 | GEO | 2025/04/06
REPOSITORIES: GEO
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Project description:The SAS-type SWI/SNF complex regulates inflorescence-specific chromatin accessibility at distal promoter and upstream intergenic regions, thereby facilitating the binding of transcription factors involved in flower development.
2025-04-06 | GSE254655 | GEO
Project description:The SAS-type SWI/SNF complex regulates inflorescence-specific chromatin accessibility at distal promoter and upstream intergenic regions, thereby facilitating the binding of transcription factors involved in flower development.
2025-04-06 | GSE254654 | GEO
Project description:Switch defective/sucrose non-fermentable (SWI/SNF) complexes are evolutionarily conserved multi-subunit machines that play vital roles in chromatin architecture regulation for modulating gene expression via sliding or ejection of nucleosomes in eukaryotes. In plants, perturbations of SWI/SNF subunits often result in severe developmental disorders. However, the subunit composition, pathways of assembly, and genomic targeting of the plant SWI/SNF complexes remain undefined. Here, we reveal that Arabidopsis SWI/SNF complexes exist in three distinct final form assemblies: BRM-associated SWI/SNF complexes (BAS), SYD-associated SWI/SNF complexes (SAS) and MINU-associated SWI/SNF complexes (MAS). We show that BAS complexes are equivalent to human ncBAF, whereas SAS and MAS complexes evolve in multiple subunits unique to plants, suggesting a plant-specific functional evolution of SWI/SNF complexes. We further demonstrate overlapping and specific genomic targeting of the three plant SWI/SNF complexes on chromatin and reveal that SAS complexes are necessary for the correct genomic localization of the BAS complexes. Finally, by focusing on the SAS and BAS complexes, we establish a requirement for both the core module subunit and the ATPase in the assembly of the plant SWI/SNF complexes. Together, our work highlights the divergence of SWI/SNF chromatin remodelers during the eukaryote evolution and provides a comprehensive landscape for understanding the plant SWI/SNF complexes organization, assembly, genomic targeting, and function.
2023-04-24 | GSE218841 | GEO
Project description:The SWI/SNF (or BAF) complex is an essential chromatin remodeler that regulates DNA accessibility at developmental genes and enhancers. SWI/SNF subunits are among the most frequently mutated genes in cancer and neurodevelopmental disorders. These mutations are often heterozygous loss-of-function alleles, indicating a dosage-sensitive role for SWI/SNF subunits in chromatin regulation. However, the molecular mechanisms that regulate SWI/SNF subunit dosage to ensure proper complex assembly remain largely unexplored. We performed a genome-wide CRISPR KO screen, using epigenome editing in mouse embryonic stem cells, and identified Mlf2 and Rbm15 as regulators of SWI/SNF complex activity. First, we show that MLF2, a poorly characterized chaperone protein, regulates a subset of SWI/SNF target genes by promoting its chromatin remodeling activity. Rapid degradation of MLF2 reduces chromatin accessibility at sites that depend on high levels of SWI/SNF binding to maintain open chromatin. Next, we find that RBM15, part of the m6A RNA methylation writer complex, controls m6A modifications on specific SWI/SNF mRNAs to regulate protein levels of these subunits. Misregulation of m6A methylation causes overexpression of core SWI/SNF subunits leading to the assembly of incomplete complexes lacking the catalytic ATPase/ARP subunits. These data indicate that targeting modulators of SWI/SNF complex assembly may offer a potent therapeutic strategy for diseases associated with impaired chromatin remodeling.
2025-04-28 | PXD061408 | Pride
Project description:The SWI/SNF (or BAF) complex is an essential chromatin remodeler that regulates DNA accessibility at developmental genes and enhancers. SWI/SNF subunits are among the most frequently mutated genes in cancer and neurodevelopmental disorders. These mutations are often heterozygous loss-of-function alleles, indicating a dosage-sensitive role for SWI/SNF subunits in chromatin regulation. However, the molecular mechanisms that regulate SWI/SNF subunit dosage to ensure proper complex assembly remain largely unexplored. We performed a genome-wide CRISPR KO screen, using epigenome editing in mouse embryonic stem cells, and identified Mlf2 and Rbm15 as regulators of SWI/SNF complex activity. First, we show that MLF2, a poorly characterized chaperone protein, regulates a subset of SWI/SNF target genes by promoting its chromatin remodeling activity. Rapid degradation of MLF2 reduces chromatin accessibility at sites that depend on high levels of SWI/SNF binding to maintain open chromatin. Next, we find that RBM15, part of the m6A RNA methylation writer complex, controls m6A modifications on specific SWI/SNF mRNAs to regulate protein levels of these subunits. Misregulation of m6A methylation causes overexpression of core SWI/SNF subunits leading to the assembly of incomplete complexes lacking the catalytic ATPase/ARP subunits. These data indicate that targeting modulators of SWI/SNF complex assembly may offer a potent therapeutic strategy for diseases associated with impaired chromatin remodeling.
2025-04-28 | PXD054392 | Pride
Project description:A systems understanding of nuclear organization and events is critical for determining how cells divide, differentiate and respond to stimuli and for identifying the causes of diseases. Chromatin remodeling complexes such as SWI/SNF have been implicated in a wide variety of cellular processes including gene expression, nuclear organization, centromere function and chromosomal stability, and mutations in SWI/SNF components have been linked to several types of cancer. To better understand the biological processes in which chromatin remodeling proteins participate we globally mapped binding regions for several components of the SWI/SNF complex throughout the human genome using ChIP-Seq. SWI/SNF components were found to lie near regulatory elements integral to transcription (e.g. 5M-bM-^@M-^Y ends, RNA Polymerases II and III and enhancers) as well as regions critical for chromosome organization (e.g. CTCF, lamins and DNA replication origins). To further elucidate the association of SWI/SNF subunits with each other as well as with other nuclear proteins we also analyzed SWI/SNF immunoprecipitated complexes by mass spectrometry. Individual SWI/SNF factors are associated with their own family members as well as with cellular constituents such as nuclear matrix proteins, key transcription factors and centromere components implying a ubiquitous role in gene regulation and nuclear function. We find an overrepresentation of both SWI/SNF-associated regions and proteins in cell cycle and chromosome organization. Taken together the results from our ChIP and immunoprecipitation experiments suggest that SWI/SNF facilitates gene regulation and genome function more broadly and through a greater diversity of interactions than previously appreciated. ChIP-Seq analysis of the SWI/SNF subunits Ini1, Brg1, BAF155 and BAF170 in HeLa S3 cells
2011-01-10 | E-GEOD-24397 | biostudies-arrayexpress
Project description:Tissue-specific transcription factors initiate differentiation toward a specialized cell type by inducing transcription-permissive chromatin modifications at target gene promoters, through the recruitment of the SWI/SNF chromatin-remodeling complex (1, 2). The molecular mechanism that regulates the chromatin re-distribution of SWI/SNF in response to differentiation signals is currently unknown. Here we show that the muscle determination factor MyoD and the SWI/SNF structural sub-unit, BAF60c (SMARCD3), form a complex on the regulatory elements of MyoD-target genes in undifferentiated myoblasts, prior to the activation of gene expression. MyoD-BAF60c complex is devoid of the ATP-dependent enzymatic sub-units Brg1 and Brm, is required for stable MyoD binding to Ebox sequences, and marks the chromatin for signal-dependent recruitment of the SWI/SNF core complex to muscle loci. BAF60c phosphorylation on a conserved threonine by differentiation-activated p38 signalling promotes the incorporation of MyoD-BAF60c into a Brg1-based SWI/SNF complex, which is competent to remodel the chromatin and activates transcription of MyoD-target genes. Our data support an unprecedented two-step model, by which pre-assembled BAF60c-MyoD complex directs the SWI/SNF complex chromatin re-distribution to muscle loci in response to differentiation cues. Differentiation of C2C12 cells individually interfered for BRG1, BAF60B, BAF60C
2011-03-07 | E-GEOD-24573 | biostudies-arrayexpress
Project description:The current studies show that JMJD1A is phosphorylated at S265 by protein kinase A (PKA), and this is pivotal to activate expression of the b1-adrenergic receptor gene (Adrb1) and downstream targets including Ucp1. Phosphorylation of JMJD1A increases its interaction with the SWI/SNF nucleosome remodeling complex and DNA-bound PPARg. This complex conferred b-adrenergic-induced JMJD1A recruitment to target sites throughout the genome. Phospho-JMJD1A also facilitated long-range chromatin looping to recruit PPARg-bound distal-enhancers, SWI/SNF, and RNA polymerase close to the Adrb1 locus to activate transcription. Mutation of the PKA-phosphorylation site on JMJD1A abolished interactions with SWI/SNF without affecting demethylase activity suggesting the two functions are independent of each other. Our results show that JMJD1A demethylase is also a signal-sensing scaffold that regulates cAMP-responsive transcription via interactions with SWI/SNF and hormone stimulated higher-order chromatin conformational changes. There are 3 samples analyzed. No duplication from each sample. Isoproterenol stimulation at 0hr is used as the relative to fold change in manuscript.
2015-04-15 | E-GEOD-58936 | biostudies-arrayexpress
Project description:In eukaryotes, ATP-dependent chromatin remodelers regulate gene expression in response to nutritional and metabolic stimuli. The Swi-Snf complex is one such remodeler that has been implicated in disease, where loss of Swi-Snf function leads to dysregulated gene transcription. However, altered transcription of metabolic genes may have consequences for entire pathways that remain poorly understood. In this study, we use genetic and molecular approaches to uncover a role for Swi-Snf as a critical regulator of metabolism. We find that Δsnf mutants are cysteine-deficient, despite growth in nutrient-rich media. This cysteine deficiency causes widespread perturbations in sulfur metabolic gene transcription. This includes global alteration and redistribution of the transcription factor Met4 which senses cysteine deficiency and also has roles in heavy metal stress response and cell cycle progression. Additionally, we show that in its role as a metabolic regulator, Swi-Snf is a critical determinant of survival following oxidative stress. Our findings show how a chromatin remodeler can have a significant impact on a whole metabolic pathway by directly regulating an important gene subset and demonstrate an emerging role for chromatin remodeling complexes as key determinants of metabolic control.
2023-08-22 | GSE197917 | GEO
Project description:• Evolutionarily conserved SWI-SNF ATP-dependent chromatin remodeling complexes (CRCs) change nucleosome positioning and chromatin states, affecting gene expression to regulate important regulatory processes controlling such as proper development and hormonal signalling pathways. • In our study we used transcript profiling, chromatin immunoprecipitation (ChIP), exhaustive protein-protein interaction study including mass-spectrometry, yeast-two-hybrid and bimolecular fluorescence complementation (BiFC) along with hormone and metabolite profiling, and phenotype assessments to distinguish the functions of Arabidopsis SWP73A and SWP73B subunits in Arabidopsis. • We identified a novel subclass of SWI/SNF chromatin remodelling complexes defined by the presence of SWP73A subunit. Therefore, we propose a refined classification of SWI/SNF CRCs in Arabidopsis, introducing BAS-A (SWP73A-containing) and BAS-B (SWP73B-containing) subclasses. The SWP73A and SWP73B-carrying subclasses of SWI/SNF CRCs exhibit differential properties demonstrated by distinct chromatin binding patterns and divergent effect on hormone biosynthesis and metabolism. We found that SWP73A plays a specific role that cannot be fully compensated by SWP73B. We recognized that some atypical subclasses of SWI/SNF CRCs may be likely formed in mutant lines with inactivated SWP73 subunits. • Our study reveals that the duplication of the SWP73 subunit contributes to unique and shared functions of subclasses of SWI/SNF CRCs in the control of various regulatory processes in Arabidopsis.
2025-04-15 | PXD056187 | Pride