The effect of bound RSC/nucleosome complex on chromatin architecture and gene expression at the GAL genes of yeast
Ontology highlight
ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE20078 | GEO | 2010/05/01
SECONDARY ACCESSION(S): PRJNA124271
REPOSITORIES: GEO
Similar Datasets
Project description:How is chromatin architecture established and what role does it play in activation of transcription? We show that a regulatory locus in yeast (the UASg) bears, in addition to binding sites for the activator Gal4, sites bound by the protein RSC. RSC tightly positions a nucleosome, evidently partially unwound, in a structure that facilitates Gal4 binding to its sites. The complex comprises a barrier that suffices to impose characteristic features of chromatin architecture. Removal of RSC allows ordinary nucleosomes to form more broadly over the UASg, and these nucleosomes compete with (but do not exclude) Gal4 binding to its sites. Taken with our previous work, the results show that both prior to and following induction specific DNA binding proteins are the predominant determinants of chromatin architecture at the GAL1/10 genes. RSC/nucleosome complexes are found scattered throughout the yeast genome. We surmise, also, that Gal4 works in higher eukaryotes despite whatever obstacle broadly positioned nucleosomes present. Chromatin was digested under conditions that yielded primarily mononucleosomes, and RSC-bearing fragments were recovered on IgG-beads. Fragments (of size ca. 50-200 bp) were analyzed by paired-end high throughput DNA sequencing (Illumina). This technique determines the sequences found at both ends of each fragment, thus revealing the sizes and genomic origin of these fragments.
2010-05-01 | E-GEOD-20078 | biostudies-arrayexpress
Project description:The chromatin architecture of eukaryotic gene promoters is generally characterized by a nucleosome-free region (NFR) flanked by at least one H2A.Z variant nucleosome. Computational predictions of nucleosome positions based on thermodynamic properties of DNA-histone interactions have met with limited success. Here we show that the action of the essential RSC remodeling complex in S. cerevisiae helps explain the discrepancy between theory and experiment. In RSC-depleted cells, NFRs shrink such that the average positions of flanking nucleosomes move toward predicted sites. Nucleosome positioning at distinct subsets of promoters additionally requires the essential Myb family proteins Abf1 and Reb1, whose binding sites are enriched in NFRs. In contrast, H2A.Z deposition is dispensable for nucleosome positioning. By regulating H2A.Z deposition using a steroid-inducible protein splicing strategy, we show that NFR establishment is necessary for H2A.Z deposition. These studies suggest an ordered pathway for the assembly of promoter chromatin architecture.
2009-05-01 | GSE13446 | GEO
Project description:ATP-dependent chromatin remodelers (CRs), including SWI/SNF, RSC and Ino80C in budding yeast, are thought to stimulate transcription by repositioning or evicting promoter nucleosomes. The relative importance of these CRs in stimulating activator binding and recruitment of TATA-binding protein (TBP) to promoters is incompletely understood. Examining mutants depleted of the catalytic subunits of these CRs, we determined that RSC and Ino80C stimulate binding of transcription factor Gcn4 to nucleosome-depleted regions, or linkers between genic nucleosomes, at multiple target genes activated by Gcn4 in amino acid-starved cells, frequently by evicting nucleosomes from the Gcn4 binding motifs. At some genes, SWI/SNF functionally complements RSC, while opposing RSC at others to limit Gcn4 binding. The CRs in turn are recruited by Gcn4 to establish positive or negative feedback loops that control Gcn4 binding. The three CRs also cooperate to enhance TBP recruitment, again involving nucleosome depletion, at both Gcn4 target genes and highly expressed ribosomal protein genes, whereas only RSC and Ino80C act broadly throughout the genome to enhance this key step in preinitiation complex assembly. Our findings illuminate functional cooperation among multiple CRs in regulating activator binding and promoter activation.
2021-12-29 | GSE192592 | GEO
Project description:Here we present evidence that precise positioning of the +1 promoter nucleosome in yeast is critical for efficient TBP binding and pre-initiation complex assembly, and is determined, at least in part, by the action of two key factors, the essential chromatin remodeler RSC and one (or more) of a small set of ubiquitous pioneer transcription factors (PTFs). Despite their widespread co-localization, we show that RSC and PTFs often act independently to generate accessible chromatin. Furthermore, we present evidence that RSC binding, as well as the strength and directionality of its action on nucleosomes, depends upon the arrangement of two specific DNA motifs relative to nearby PTF binding sites. Our results provide insights into how promoter DNA sequence instructs trans-acting factors to precisely control nucleosome architecture and stimulate transcription initiation.
2018-06-01 | GSE98259 | GEO
Project description:Here we present evidence that precise positioning of the +1 promoter nucleosome in yeast is critical for efficient TBP binding and pre-initiation complex assembly, and is determined, at least in part, by the action of two key factors, the essential chromatin remodeler RSC and one (or more) of a small set of ubiquitous pioneer transcription factors (PTFs). Despite their widespread co-localization, we show that RSC and PTFs often act independently to generate accessible chromatin. Furthermore, we present evidence that RSC binding, as well as the strength and directionality of its action on nucleosomes, depends upon the arrangement of two specific DNA motifs relative to nearby PTF binding sites. Our results provide insights into how promoter DNA sequence instructs trans-acting factors to precisely control nucleosome architecture and stimulate transcription initiation.
2018-06-01 | GSE98205 | GEO
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:The chromatin architecture of eukaryotic gene promoters is generally characterized by a nucleosome-free region (NFR) flanked by at least one H2A.Z variant nucleosome. Computational predictions of nucleosome positions based on thermodynamic properties of DNA-histone interactions have met with limited success. Here we show that the action of the essential RSC remodeling complex in S. cerevisiae helps explain the discrepancy between theory and experiment. In RSC-depleted cells, NFRs shrink such that the average positions of flanking nucleosomes move toward predicted sites. Nucleosome positioning at distinct subsets of promoters additionally requires the essential Myb family proteins Abf1 and Reb1, whose binding sites are enriched in NFRs. In contrast, H2A.Z deposition is dispensable for nucleosome positioning. By regulating H2A.Z deposition using a steroid-inducible protein splicing strategy, we show that NFR establishment is necessary for H2A.Z deposition. These studies suggest an ordered pathway for the assembly of promoter chromatin architecture. Nucleosome positions were mapped in a variety of strains under a variety of conditions to determine how several proteins are involved in nucleosome positioning. All replicates are biological replicates. Each set of replicates is balanced in terms of Cy3:Cy5 such that there are equal numbers of Cy3:Cy5 and Cy5:Cy3 arrays (format: mononucleosomal DNA:reference DNA). Changes in gene expression in a strain carrying either the Sth1-degron or Abf1-Reb1-degron under degron-inducing conditions were profiled by hybridizing labeled cDNA derived from the degron strain against labeled cDNA derived from a control strain lacking the degron, but grown under the same conditions. Four biological replicates for each experiment were done using a balanced dye-swap design.
2009-04-30 | E-GEOD-13446 | biostudies-arrayexpress
Project description:Nucleosomes in active chromatin are dynamic, but whether they have distinct structural conformations is unknown. To identify nucleosomes with alternative structures genome-wide, we used H4S47C-anchored cleavage mapping, which revealed that nucleosomes at 5% of budding yeast nucleosome positions have asymmetric histone-DNA interactions. These asymmetric interactions are enriched at nucleosome positions that flank promoters. Micrococcal nuclease (MNase) sequence-based profiles of asymmetric nucleosome positions revealed a corresponding asymmetry in MNase protection near the dyad axis, suggesting that the loss of DNA contacts around H4S47 is accompanied by protection of the DNA from MNase. Chromatin immunoprecipitation mapping of selected nucleosome remodelers indicated that asymmetric nucleosomes are bound by the RSC chromatin remodeling complex, which is required for maintaining nucleosomes at asymmetric positions. These results imply that the asymmetric nucleosome-RSC complex is a metastable intermediate representing partial unwrapping and protection of nucleosomal DNA on one side of the dyad axis during chromatin remodeling. We have analyzed the chromatin landscape of the yeast genome using paired-end MNase-seq and the chromatin binding of yeast remodelers Swr1, Ino80 and RSC at base-pair resolution using native chromatin immunoprecipitation followed by sequencing (N-ChIP-seq).
2014-12-04 | E-GEOD-59523 | biostudies-arrayexpress
Project description:Nucleosome arrays begin at nucleosome-free promoter regions (NFRs) and regulate gene expression. Reconstituting such organization throughout a genome with purified proteins is a critical challenge in establishing biochemical mechanisms for chromosome assembly. Here we establish a four-step hierarchical building plan for yeast genomic nucleosome organization using only purified components: genomic DNA, histones, site-specific organizing factors Abf1 and Reb1, and the chromatin remodelers RSC, ISW2, INO80, and ISW1a. First, RSC makes NFRs by translating promoter poly(dA:dT) tracts into directional nucleosome removal. Second, +1 nucleosomes are positioned by INO80 at most genes potentially involving DNA shape, or by ISW2 using gene-specific Abf1 and Reb1. Third, INO80 or ISW2 create arrays with wide spacing. Fourth, ISW1a tightens the spacing and creates properly positioned arrays. We conclude that entire genomes use a simple set of rules and proteins, without transcription, to build a common chromatin architecture. In this study, nucleosomes were assembled using Salt Gradient Dialysis (SGD) on yeast genomic DNA library. Assembled nucleosomes were either left untreated (labelled as "SGD", control), treated with whole cell extract (WCE), mutant extracts (rsc3ts WCE, isw1 isw2 chd1 WCE), purified remodelers; singly or in combinations (RSC, ISW1a, ISW1b, ISW2, INO80, CHD1, SWI/SNF), combinations of mutant extracts and chromatin remodelers or combination of General Regulatory Factors (Abf1, Reb1) and chromatin remodelers. The resulting nucleosome positions were mapped genome-wide using MNase-(anti-H3-ChIP)-Seq.
2016-08-14 | E-GEOD-72106 | biostudies-arrayexpress
Project description:Nucleosomes restrict the access of transcription factors to chromatin. RSC is a SWI/SNF-family chromatin-remodeling complex from yeast that repositions and ejects nucleosomes in vitro. Here, we examined these activities and their importance in vivo. We utilized array-based methods to examine nucleosome occupancy and positioning at more than 200 locations in the genome following the controlled destruction of the catalytic subunit of RSC, Sth1. Loss of RSC function caused pronounced and general reductions in transcription from Pol I, II, and III genes. At Pol III genes, Sth1 loss conferred a general gain in nucleosome density and an accompanying reduction in RNA Pol III occupancy. In contrast, we observed primarily single nucleosome changes, including movement, at Pol II promoters. Importantly, a greater number of changes were observed near the transcription start sites of RSC-occupied promoters than non-occupied promoters. These changes are distinct from those due to general loss of transcription. Thus, RSC action affects both nucleosome density and positioning in vivo, but applies these remodeling modes differently at Pol II and Pol III genes. Keywords: ChIP-chip, nucleosome, mononucleosome, RSC, transcription
2007-12-01 | GSE8862 | GEO