SWI/SNF and RSC cooperate to reposition and evict promoter nucleosomes at highly expressed genes in yeast
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PROVIDER: PRJNA433556 | ENA |
REPOSITORIES: ENA
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Project description:The nucleosome remodeling complex RSC functions throughout the yeast genome to set the positions of -1 and +1 nucleosomes and thereby determines the widths of nucleosome-depleted regions (NDRs). The related complex SWI/SNF participates in nucleosome remodeling/eviction and promoter activation at certain yeast genes, including those activated by transcription factor Gcn4, but does not appear to function broadly in establishing NDRs. By analyzing the large cohort of Gcn4-induced genes in mutants lacking the catalytic subunits of SWI/SNF or RSC, we uncovered cooperation between these remodelers in evicting nucleosomes from different locations in the promoter and in repositioning the +1 nucleosome downstream to produce wider NDRs, highly depleted of nucleosomes, during transcriptional activation. SWI/SNF also functions on par with RSC at the most highly transcribed constitutively expressed genes, suggesting general cooperation by these remodelers for maximal transcription. SWI/SNF and RSC occupancies are greatest at the most highly expressed genes, consistent with their cooperative functions in nucleosome remodeling and transcriptional activation. Thus, SWI/SNF acts comparably to RSC in forming wide, nucleosome-free NDRs to achieve high-level transcription, but only at the most highly expressed genes exhibiting the greatest SWI/SNF occupancies.
2018-03-23 | GSE110379 | GEO
Project description:SWI/SNF chromatin remodeling complexes play critical roles in transcription and other chromatin-related processes. The analysis of the two members of this class in Saccharomyces cerevisiae, SWI/SNF and RSC, has heavily contributed to our understanding of these complexes. To understand the in vivo functions of SWI/SNF and RSC in an evolutionarily distant organism, we have characterized these complexes in Schizosaccharomyces pombe. While core components are conserved between the two yeasts, the compositions of S. pombe SWI/SNF and RSC differ from their S. cerevisiae counterparts and in some ways are more similar to metazoan complexes. Furthermore, several of the conserved proteins, including actin-like proteins, are strikingly different between the two yeasts with respect to their requirement for viability. Finally, phenotypic and microarray analyses identified widespread requirements for SWI/SNF and RSC on transcription including strong evidence that SWI/SNF directly represses iron transport genes.
2008-06-13 | E-MTAB-31 | biostudies-arrayexpress
Project description:SWI/SNF-family chromatin remodelling complexes conduct nucleosome sliding and ejection to provide DNA-binding proteins access to their sites in chromatin. RSC is an essential and abundant SWI/SNF-family chromatin remodeller from S. cerevisiae that both slides and ejects nucleosomes. However, how ejection versus sliding is chosen, regulated and implemented by any remodeller remains largely unknown. The RSC catalytic subunit Sth1 conducts ATP-dependent DNA translocation, pumping DNA around the nucleosome, providing a property that might underlie both sliding and ejection. Sth1 shares with other SWI/SNF-family ATPases direct binding to two nuclear actin-related proteins (ARPs), but how ARPs impact DNA translocation, sliding and ejection is unknown. Here, we reveal that nucleosome ejection by RSC requires ARPs, and that ARPs improve ‘coupling’ – the efficiency of DNA translocation by Sth1 relative to ATP hydrolysis – thus, enhancing DNA translocation. We further characterize two domains within Sth1 (termed PTH and P1), showing they separately regulate ATP hydrolysis or ‘coupling’, respectively. Interestingly, gain-of-function PTH or P1 mutations suppress arpΔ lethality, and improve ATPase or coupling activities, enabling Sth1 to efficiently slide and eject nucleosomes without ARPs. Moreover, PTH mutations greatly improved DNA translocation velocity. Overall, our results provide a logic for regulating nucleosome sliding versus ejection: both modes involve DNA translocation, but ejection requires a higher magnitude. Here, low-to-moderate ATPase and coupling activity integrate to confer low-to-moderate sliding, whereas high ATPase and/or coupling combine to provide efficient and rapid DNA translocation, consistent with the simultaneous rupture of multiple histone-DNA contacts, causing histone loss/ejection. Our discovery of an ARP module and regulatory domains that regulate sliding and ejection suggests a mechanistic platform through which activators and histone epitopes may guide the remodelling outcome of SWI/SNF-family chromatin remodellers.
2016-05-01 | GSE68533 | GEO
Project description:Nucleosomes are a significant barrier to the repair of UV damage because they impede damage recognition by nucleotide excision repair (NER). The RSC and SWI/SNF chromatin remodelers function in cells to promote DNA access by moving or evicting nucleosomes and both have been linked to NER in yeast. Here, we report genome-wide repair maps of UV-induced cyclobutane pyrimidine dimers (CPDs) in yeast cells lacking RSC or SWI/SNF activity. Our data indicate that SWI/SNF is not generally required for NER, but instead promotes repair of CPD lesions at specific yeast genes. In contrast, mutation or depletion of RSC subunits causes a general defect in NER across the yeast genome. Our data indicate that RSC is required for repair not only in nucleosomal DNA, but also neighboring linker DNA and nucleosome-free regions (NFRs). Intriguingly, while depletion of the RSC catalytic subunit also affects base excision repair (BER) of N-methylpurine (NMP) lesions, RSC activity is less important for BER in linker DNA and NFRs. Furthermore, our data indicate that RSC plays a direct role in transcription coupled-NER (TC-NER) of transcribed DNA. These findings help to define the specific genomic and chromatin contexts in which each chromatin remodeler functions in DNA repair, and indicate that RSC plays a unique function in facilitating repair by both NER subpathways.
2021-04-12 | GSE161929 | GEO
Project description:ISWI-family chromatin remodelers organize nucleosome arrays, while SWI/SNF-family remodelers (RSC) disorganize and eject nucleosomes, implying an antagonism that is largely unexplored in vivo. Here, we describe two independent genetic screens for rsc suppressors that yielded mutations in the promoter-focused ISW1a complex, or mutations in the ‘basic patch’ of histone H4 (an epitope that regulates ISWI activity), strongly supporting RSC-ISW1a antagonism in vivo. RSC and ISW1a largely co-localize, and genomic nucleosome studies using rsc isw1 mutant combinations revealed opposing functions: promoters classified with a nucleosome-deficient region (NDR) gain nucleosome occupancy in rsc mutants, but this gain is attenuated in rsc isw1 double mutants. Furthermore, promoters lacking NDRs have the highest occupancy of both remodelers, consistent with regulation by nucleosome occupancy, and decreased transcription in rsc mutants. Taken together, we provide the first genetic and genomic evidence for RSC-ISW1a antagonism, and reveal different mechanisms at two different promoter architectures. Genomic localization of RSC, ISW1a, and SWI/SNF complexes were measured by chromatin immunoprecipitation followed by Illumina paired-end sequencing. Four strains were analyzed, including Rsc8-9xMyc (YBC2882), Sth1-2xFlag (YBC601 p3018), Ioc3-13xMyc (YBC2883), and Snf2-13xMyc (YBC3010). Each sample consists of one chromatin immunoprecipitate and one input chromatin control.
2015-04-01 | E-GEOD-65592 | biostudies-arrayexpress
Project description:Eukaryotic DNA is packaged into nucleosome arrays, which are repositioned by chromatin remodeling complexes to control DNA accessibility. The Saccharomyces cerevisiae RSC (Remodeling the Structure of Chromatin) complex, a member of the SWI/SNF chromatin remodeler family, plays critical roles in genome maintenance, transcription, and DNA repair. Here, we report cryo-electron microscopy (cryo-EM) and crosslinking mass spectrometry (CLMS) studies of yeast RSC complex and show that RSC is composed of a rigid tripartite core and two flexible lobes. The core structure is scaffolded by an asymmetric Rsc8 dimer and built with the evolutionarily conserved subunits Sfh1, Rsc6, Rsc9 and Sth1. The flexible ATPase lobe, composed of helicase subunit Sth1, Arp7, Arp9 and Rtt102, is anchored to this core by the N-terminus of Sth1. Our cryo-EM analysis of RSC bound to a nucleosome core particle shows that in addition to the expected nucleosome-Sth1 interactions, RSC engages histones and nucleosomal DNA through one arm of the core structure, composed of the Rsc8 SWIRM domains, Sfh1 and Npl6. Our findings provide structural insights into the conserved assembly process for all members of the SWI/SNF family of remodelers, and illustrate how RSC selects, engages, and remodels nucleosomes.
2020-05-27 | PXD019400 | Pride
Project description: Not available
| S-EPMC6004078 | biostudies-literature
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: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 | MSV000081417 | MassIVE
Project description:The chromatin remodelers (CRs) SWI/SNF and RSC function in evicting promoter nucleosomes at highly expressed yeast genes, particularly those activated by transcription factor Gcn4. Ino80 remodeling complex (Ino80C) can establish nucleosome-depleted regions (NDRs) in reconstituted chromatin, and was implicated in removing histone variant H2A.Z from the -1 and +1 nucleosomes flanking NDRs; however, Ino80C’s function in transcriptional activation in vivo is not well understood. Analyzing the cohort of Gcn4-induced genes in ino80Δ mutants has uncovered a role for Ino80C on par with SWI/SNF in evicting promoter nucleosomes and transcriptional activation. Compared to SWI/SNF, Ino80C generally functions over a wider region, spanning the -1 and +1 nucleosomes, NDR, and proximal genic nucleosomes, at genes highly dependent on its function. Defects in nucleosome eviction in ino80Δ cells are frequently accompanied by reduced promoter occupancies of TBP, and diminished transcription; and Ino80 is enriched at genes requiring its remodeler activity. Importantly, nuclear depletion of Ino80 impairs promoter nucleosome eviction even in a mutant lacking H2A.Z. Thus, Ino80C acts widely in the yeast genome together with RSC and SWI/SNF in evicting promoter nucleosomes and enhancing transcription, all in a manner at least partly independent of H2A.Z editing.
2019-12-24 | GSE142273 | GEO