Schizosaccharomyces pombe
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ABSTRACT:
PROVIDER: PRJNA175270 | ENA |
REPOSITORIES: ENA
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Project description:Proper chromatin organization is essential for defining transcription units and maintaining genomic integrity in eukaryotes. Mutations affecting the chromatin structure can lead to increased cryptic transcription and genomic instability. In this study we found that deletion of the Schizosaccharomyces pombe Chd1-type chromatin remodelers, hrp1 and hrp3, causes strong, genome-wide accumulation of antisense transcripts, while the amount of coding mRNA transcripts is mostly unaffected. Nucleosome mapping revealed a specific role for Chd1-remodelers in the positioning of nucleosomes in gene coding regions. While the arrangement of nucleosomes in promoter regions was similar to WT, nucleosome organization within coding regions was remarkably irregular in hrp1∆hrp3∆ strain. We extended our analysis to other mutations associated with enhanced cryptic transcription activity, such as set2∆, alp13∆, and FACT complex subunit pob3∆. While nucleosomes were severely depleted in the pob3∆ strain, nucleosome positioning was less affected. In sharp contrast, nucleosome organization in the alp13∆ and set2∆ strains was indistinguishable from WT. These data indicate multiple mechanisms in the repression of cryptic promoter activity in eukaryotic cells. Genome-wide profiling of H3K9/K14 acetylation Genome-wide expression analysis of either Alp13-, Set2-, Hrp3 or Hrp1 and Hrp3-deficient cells Genome-wide expression analysis of either Hrp1, Hrp3, or Hrp1 and Hrp3-deficient cells Nucleosome mapping experiments
2012-09-15 | GSE40872 | GEO
Project description:Chromatin remodelers are ATP-dependent enzymes that reorganize nucleosomes within all eukaryotic genomes. The Chd1 remodeler specializes in shifting nucleosomes into evenly spaced arrays, a defining characteristic of chromatin in gene bodies that blocks spurious transcription initiation. Linked to some forms of autism and commonly mutated in prostate cancer, Chd1 is essential for maintaining pluripotency in stem cells. Here we report a complex of yeast Chd1 bound to a nucleosome in a nucleotide-free state, determined by cryo-electron microscopy (cryo-EM) to 2.6 Å resolution. The structure shows a bulge of the DNA tracking strand where the ATPase motor engages the nucleosome, consistent with an initial stage in DNA translocation. Unlike other remodeler-nucleosome complexes, nucleosomal DNA compensates for the remodeler-induced bulge with a bulge of the complementary DNA strand one helical turn downstream from the ATPase motor. Unexpectedly, the structure also reveals an N-terminal binding motif, called ChEx, which binds on the exit-side acidic patch of the nucleosome. The ChEx motif can displace a LANA-based peptide from the acidic patch, which suggests a means by which Chd1 remodelers may block competing chromatin remodelers from acting on the opposite side of the nucleosome.
2022-02-23 | PXD025287 | Pride
Project description:Proper chromatin organization is essential for defining transcription units and maintaining genomic integrity in eukaryotes. Mutations affecting the chromatin structure can lead to increased cryptic transcription and genomic instability. In this study we found that deletion of the Schizosaccharomyces pombe Chd1-type chromatin remodelers, hrp1 and hrp3, causes strong, genome-wide accumulation of antisense transcripts, while the amount of coding mRNA transcripts is mostly unaffected. Nucleosome mapping revealed a specific role for Chd1-remodelers in the positioning of nucleosomes in gene coding regions. While the arrangement of nucleosomes in promoter regions was similar to WT, nucleosome organization within coding regions was remarkably irregular in hrp1M-bM-^HM-^Fhrp3M-bM-^HM-^F strain. We extended our analysis to other mutations associated with enhanced cryptic transcription activity, such as set2M-bM-^HM-^F, alp13M-bM-^HM-^F, and FACT complex subunit pob3M-bM-^HM-^F. While nucleosomes were severely depleted in the pob3M-bM-^HM-^F strain, nucleosome positioning was less affected. In sharp contrast, nucleosome organization in the alp13M-bM-^HM-^F and set2M-bM-^HM-^F strains was indistinguishable from WT. These data indicate multiple mechanisms in the repression of cryptic promoter activity in eukaryotic cells. Genome-wide profiling of H3K9/K14 acetylation Genome-wide expression analysis of either Alp13-, Set2-, Hrp3 or Hrp1 and Hrp3-deficient cells Genome-wide expression analysis of either Hrp1, Hrp3, or Hrp1 and Hrp3-deficient cells Nucleosome mapping experiments ChIP for the detection of the genome-wide acetylation profile of H3K9/K14 was performed for a wildtype strain and the deletion strains of Set2, Alp13 and the double knock-out of Hrp1 and Hrp3. Each experiment was performed twice in biological replicates All experiments were performed twice in biological replicates, except for the expression array of set2M-NM-^T. The replicates of hrp3M-NM-^T and hrp1M-NM-^Thrp3M-NM-^T were performed with a slightly different array design All experiments were performed twice in biological replicates. The replicates of hrp3M-NM-^T and hrp1M-NM-^Thrp3M-NM-^T were performed with a slightly different array design MNase treated sample were comparatively hybridized with genomic DNA of corresponding strain, WT, hrp1d hrp3d, pob3d in biological duplicates, set2d, alp13d, mit1d, hrp1d, hrp3d analysis was performed once
2012-09-15 | E-GEOD-40872 | 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:This SuperSeries is composed of the following subset Series: GSE32042: Isw1 and Chd1 maintain chromatin organization during transcription GSE32043: Histone exchange in wildtype, isw1, chd1, isw1 chd1 and ioc4 yeast strains GSE32044: Histone H3 K36me3 in wildtype, isw1 and chd1 yeast strains GSE32045: Isw1 and Chd1 maintain chromatin organization during transcription [AcH4 data] GSE36405: Isw1 and Chd1 maintain chromatin organization during transcription [K56ac data] GSE37158: Isw1 and Chd1 maintain chromatin organization during transcription [isw1 chd1 mutant expression] Refer to individual Series
2012-07-24 | E-GEOD-32071 | biostudies-arrayexpress
Project description:Most yeast genes have a nucleosome-depleted region (NDR) at the promoter and an array of regularly spaced nucleosomes phased relative to the transcription start site. We have examined the interplay between RSC (a conserved essential SWI/SNF-type complex that determines NDR size) and the ISW1, CHD1 and ISW2 nucleosome spacing enzymes in chromatin organization and transcription, using isogenic strains lacking all combinations of these enzymes. The contributions of these remodelers to chromatin organization are largely combinatorial, distinct and non-redundant, supporting a model in which the +1 nucleosome is positioned by RSC and then used as a reference nucleosome by the spacing enzymes. Defective chromatin organization correlates with altered RNA polymerase II (Pol II) distribution. RSC-depleted cells exhibit low levels of elongating Pol II and high levels of terminating Pol II, consistent with defects in both termination and initiation, suggesting that RSC facilitates both. Cells lacking both ISW1 and CHD1 show the opposite Pol II distribution, suggesting elongation and termination defects. These cells have extremely disrupted chromatin, with high levels of close-packed di-nucleosomes near the 5’-ends of genes. We propose that ISW1 and CHD1 facilitate Pol II elongation by separating close-packed nucleosomes and by eliminating long linkers to prevent cryptic initiation.
2019-01-16 | GSE117514 | GEO
Project description:CHD1 remodelers space nucleosomes in vitro and link regular arrays to 5’ ends of genes in S. Pombe
| PRJNA177319 | ENA
Project description:Chromatin remodelers influence genetic processes by altering nucleosome occupancy, positioning, and composition. In vitro, yeast ISWI and CHD remodelers require > 20 bp of extranucleosomal DNA for remodeling, but linker DNA in S. cerevisiae averages < 20 bp. To resolve this paradox, we have mapped the genomic distributions of the yeast Isw1, Isw2, and Chd1 remodelers at base-pair resolution. Surprisingly, remodelers are highly enriched at promoter nucleosome depleted regions (5' NDRs), where they bind to regions of extended linker DNA. Remodelers are also enriched in the bodies of genes displaying high nucleosome turnover. We hypothesize that remodelers bind but do not act at 5' NDRs, remaining in physical proximity to gene bodies, where they act on regions of transient nucleosome depletion following transcriptional elongation. We have analyzed the dynamics of yeast ISWI and CHD chromatin remodeler genomic association at base-pair resolution using native chromatin immunoprecipitation followed by sequencing (N-ChIP-seq).
2013-03-01 | E-GEOD-39430 | biostudies-arrayexpress
Project description:Chromatin remodelers influence genetic processes by altering nucleosome occupancy, positioning, and composition. In vitro, yeast ISWI and CHD remodelers require > 20 bp of extranucleosomal DNA for remodeling, but linker DNA in S. cerevisiae averages < 20 bp. To resolve this paradox, we have mapped the genomic distributions of the yeast Isw1, Isw2, and Chd1 remodelers at base-pair resolution. Surprisingly, remodelers are highly enriched at promoter nucleosome depleted regions (5' NDRs), where they bind to regions of extended linker DNA. Remodelers are also enriched in the bodies of genes displaying high nucleosome turnover. We hypothesize that remodelers bind but do not act at 5' NDRs, remaining in physical proximity to gene bodies, where they act on regions of transient nucleosome depletion following transcriptional elongation. We have analyzed the dynamics of yeast ISWI and CHD chromatin remodeler genomic association at base-pair resolution using native chromatin immunoprecipitation followed by sequencing (N-ChIP-seq).
2013-03-01 | E-GEOD-39431 | biostudies-arrayexpress
Project description:Hrp3_Purification from Schizosaccharomyces pombe 972h- Eukaryotic genome is composed of repeating units of nucleosomes to form chromatin arrays. A canonical gene is marked by nucleosome free region (NFR) at its 5’ end followed by uniformly spaced arrays of nucleosomes. In fission yeast we show both biochemically and in vivo that both Hrp1 and Hrp3 are key determinants of uniform spacing of genic arrays.
2014-05-16 | PXD000041 | Pride