Composition and Function of Mutant Swi/Snf Complexes.
Ontology highlight
ABSTRACT:
INSTRUMENT(S): LTQ
ORGANISM(S): Saccharomyces Cerevisiae (baker's Yeast)
SUBMITTER: 
Workman Jerry
PROVIDER: MSV000081417 | MassIVE | Mon Aug 07 06:43:00 BST 2017
REPOSITORIES: MassIVE
Similar Datasets
Project description:The 12-subunit Swi/Snf chromatin remodeling complex is conserved from yeast to humans. It functions to alter nucleosome positions by either sliding nucleosomes on DNA or evicting histones. Interestingly, 20% of all human cancers carry mutations in subunits of the Swi/Snf complex. Many of these mutations cause protein instability and loss, resulting in partial Swi/Snf complexes. Although several studies have shown that histone acetylation and activator-dependent recruitment of Swi/Snf regulate its function, it is less well understood how subunits regulate stability and function of the complex. Using functional proteomic and genomic approaches, we have assembled the network architecture of yeast Swi/Snf. In addition, we find that subunits of the Swi/Snf complex regulate occupancy of the catalytic subunit Snf2, thereby modulating gene transcription. Our findings have direct bearing on how cancer-causing mutations in orthologous subunits of human Swi/Snf may lead to aberrant regulation of gene expression by this complex.
2017-08-07 | MSV000081418 | MassIVE
Project description:We have focused our investigation on the characterization of the role of the fungal specific SWI/SNF subunit, Snf6. Our data show that, although the C. albicans subunit has only limited sequence similarity to other fungal orthologs, Snf6 was copurified with SWI/SNF complex subunits including the catalytic ATPase subunit, Snf2. We show that Snf6 plays a critical role in biological processes that are essential for fungal pathogenesis including carbon metabolic flexibility, stress response and morphogenesis. The Snf6 regulon was determined by combining both genome-wide location (ChIP-chip) and transcriptional profiling (microarrays) to identify targets of the SWI/SNF complex under both yeast- and hyphal-promoting conditions.
2017-10-28 | GSE106278 | GEO
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:Every known SWI/SNF chromatin-remodeling complex incorporates an ARID DNA binding domain-containing subunit. Despite being a ubiquitous component of these complexes, physiological roles for this domain remain undefined. We screened an N-ethyl-N-nitrosurea (ENU) mutagenized library for ARID domain point mutations and generated an Arid1a/Baf250a hypomorphic allele. The mutant ARID1a (V1068G) protein is stably expressed at wild-type levels, and it is capable of assembling into a SWI/SNF complex with in vitro mononucleosome disruption activity. However, its capacity to bind DNA is lost. Consistent with defective DNA binding, mutant protein occupancy at known SWI/SNF target genes is decreased. Loss of DNA binding is associated with concurrent changes in SWI/SNF target gene expression. Mutant embryos manifest heart defects, fail to establish proper yolk sac vasculature, and exhibit hemorrhaging. As a result of these phenotypes, mutant embryos fail to establish proper circulation, culminating in ischemic arrest in utero between days 9.5 and 11.5. These data support a role for ARID1a-containing, BAF-A complexes in heart and extraembryonic vascular development, and indicate the ARID domain of ARID1a is essential in this regard. Hence, intrinsic ARID subunit-DNA interactions are required for normal SWI/SNF function in vivo. Four-condition experiment, wild-type vs Baf250a/Arid1a^V1068G/V1068G yolk sacs isolated at E8.5 and E9.5. Biological replicates: 3 per condition.
2012-01-15 | E-GEOD-32116 | biostudies-arrayexpress
Project description:The composition of chromatin remodeling complexes dictates how these enzymes control transcriptional programs and cellular identity. Here, we investigate the composition of SWI/SNF complexes in embryonic stem cells (ESCs). In contrast to differentiated cells, ESCs have a biased incorporation of certain paralogous SWI/SNF subunits, with low levels of Brm, BAF170 and ARID1B. Upon differentiation, the expression of these subunits increases, resulting in a higher diversity of compositionally distinct SWI/SNF enzymes. We also identify Brd7 as a novel component of the PBAF complex in both ESCs and differentiated cells. Using shRNA-mediated depletion of Brg1, we show that SWI/SNF can function as both a repressor and an activator in pluripotent cells, regulating expression of developmental modifiers and signaling components such as Nodal, ADAMTS1, Bmi-1, CRABP1 and TRH. Knock-down studies of PBAF-specific Brd7 and of a signature subunit within the BAF complex, ARID1A, show that these two sub-complexes affect SWI/SNF target genes differentially, in some cases even antagonistically. This may be due to their different biochemical properties. Finally, we examine the role of SWI/SNF in regulating its target genes during differentiation. We find that SWI/SNF affects recruitment of components of the pre-initiation complex in a promoter-specific manner, to modulate transcription positively or negatively. Taken together, our results provide insight into the function of compositionally diverse SWI/SNF enzymes that underlie their inherent gene-specific mode of action. R1 ESCs were infected in duplicates with shRNA targeting Brg1 or GLUT4 (as a control). Knockdown of Brg1 mRNA affected Brg1 protein levels efficiently. RNA was isolated 67 hours post-infection and analyzed using microarrays.
2010-03-04 | E-GEOD-7791 | biostudies-arrayexpress
Project description:Mammalian SWI/SNF complexes are ATP-dependent chromatin remodelers composed of varying combinations of subunits that, together, fine-tune transcriptional regulation and genome integrity. SWI/SNF complex subunits have been identified as major targets of mutations in several tumor types suggesting a relevant role in tumorigenesis. However, there is a lack of comprehensive studies of the whole SWI/SNF complex in lung adenocarcinoma (LUAD). Here, we combined genomic, transcriptomic, and proteomic approaches to identify which SWI/SNF subunits are present in lung cells, as well as their mutational status, mRNA levels, and protein levels in LUAD. For these purposes, we combined data from LUAD primary tumors, normal lung and LUAD cell lines, and external LUAD data from The Cancer Genome Atlas. Importantly, we found that mutations in the SWI/SNF complex in LUAD not only present a high incidence but we also observed that only the mutational status of the SWI/SNF complex and not the mutations in any of the top ten LUAD driver genes is associated with poorer overall survival in LUAD patients. Furthermore, we showed that the expression of the SWI/SNF complex in LUAD suffers an overall repression that cannot be explained exclusively by genetic alterations. Based on our findings, we propose that SWI/SNF-mutant LUAD tumors should be considered as a distinct subgroup with practical applications in the prognosis and follow-up of LUAD patients.
2022-04-01 | PXD017397 | Pride
Project description:The SWI/SNF ATP-dependent chromatin remodeler is a master regulator of the epigenome; controlling pluripotency, cell fate determination and differentiation. There is a sparsity of information on the autoregulation of SWI/SNF, the domains involved and their mode of action. We find a DNA or RNA binding module conserved from yeast to humans located in the C-terminus of the catalytic subunit of SWI/SNF called the AT-hook that positively regulates the chromatin remodeling activity of yeast and mouse SWI/SNF. The AT-hook in yeast SWI/SNF interacts with the SnAC and ATPase domains, which after binding to nucleosome switches to contacting the N-terminus of histone H3. Deletion of the AT-hooks in yeast SWI/SNF and mouse esBAF complexes reduces the remodeling activity of SWI/SNF without affecting complex integrity or its recruitment to nucleosomes. In addition, deletion of the AT-hook impairs the ATPase and nucleosome mobilizing activities of yeast SWI/SNF without disrupting the interactions of the ATPase domain with nucleosomal DNA. The AT-hook is also important in vivo for SWI/SNF-dependent response to amino acid starvation in yeast and for cell lineage priming in mouse embryonic stem cells. In summary, the AT-hook is shown to be an evolutionarily conserved autoregulatory domain of SWI/SNF that positively regulates SWI/SNF both in vitro and in vivo.
2023-06-15 | PXD040664 | Pride
Project description:Loss of Swi/Snf subunits regulate transcription.
2017-02-17 | GSE81722 | GEO
Project description:SWItch/Sucrose Non-Fermenting (SWI/SNF) complexes are a family of chromatin remodellers that are conserved across eukaryotes. Mutations in subunits of SWI/SNF cause a multitude of different developmental disorders in humans, most of which have no current treatment options. Here we identify an alanine to valine causing mutation in the SWI/SNF subunit snfc-5 (SMARCB1 in humans) that prevents embryonic lethality in C. elegans nematodes harbouring a loss-of-function mutation in the SWI/SNF subunit swsn-1 (SMARCC1/2 in humans). Furthermore, we found that the combination of this specific mutation in snfc-5 and a loss-of-function mutation in either of the E3 ubiquitin ligases ubr-5 (UBR5 in humans) or hecd-1 (HECTD1 in humans) can restore development to adulthood in swsn-1 loss-of-function mutants that otherwise die as embryos. Using these mutant models, we established a set of 335 genes that are dysregulated in SWI/SNF mutants that arrest their development embryonically but exhibit near wild-type levels of expression in the presence of suppressor mutations that prevent embryonic lethality, suggesting that SWI/SNF promotes development by regulating this specific subset of genes. In addition, we show that SWI/SNF protein levels are reduced in swsn-1; snfc-5 double mutants and partly restored to wild-type levels in swsn-1; snfc-5; ubr-5 triple mutants, consistent with a model in which UBR-5 regulates SWI/SNF levels by tagging the complex for proteasomal degradation. Our findings establish a link between two E3 ubiquitin ligases and SWI/SNF function and suggest that UBR5 and HECTD1 might be viable therapeutic targets for the many developmental disorders caused by missense mutations in SWI/SNF subunits.
2023-01-24 | PXD037497 | Pride
Project description:For cells to initiate and sustain a differentiated state, it is necessary that a “memory” of this state is transmitted through mitosis to the daughter cells. Mammalian SWItch/ Sucrose Non- Fermentable (SWI/SNF) complexes, also called Brg1/ Brg- associated factors (BAF), control cell identity by modulating chromatin architecture to regulate gene expression, but whether they participate in cell fate memory is unclear. Here, we provide evidence that subunits of SWI/SNF act as mitotic bookmarks to safeguard cell identity during cell division. The SWI/SNF core subunits SMARCE1 and SMARCB1 are displaced from enhancers but bound on promoters during mitosis and we show that this binding is required for appropriate reactivation of bound genes after mitotic exit. Ablation of SMARCE1 during a single mitosis in mouse embryonic stem cells is sufficient to disrupt gene expression, impair the occupancy of several established bookmarks at a subset of their targets, and cause aberrant neural differentiation. Thus, SWI/SNF subunit SMARCE1 plays a mitotic bookmarking role and is essential for heritable epigenetic fidelity during transcriptional reprogramming.
2023-03-18 | GSE189563 | GEO