Comparative genomics reveals Chd1 as a determinant of nucleosome spacing in vivo
Ontology highlight
ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE66979 | GEO | 2015/03/18
SECONDARY ACCESSION(S): PRJNA278642
REPOSITORIES: GEO
Similar Datasets
Project description:We addressed the roles of three nucleosome spacing enzymes (ISW1, ISW2 and CHD1) in specifying chromatin organization in S. cerevisiae.
2016-02-17 | GSE69400 | GEO
Project description:We addressed the roles of three nucleosome spacing enzymes (ISW1, ISW2 and CHD1) in specifying chromatin organization in S. cerevisiae. Comparison of budding yeast nucleosome positions obtained using micrococcal nuclease digestion followed by paired-end sequencing (MNase-seq). We sequenced nucleosomes from isogenic strains with the isw1Î, isw2Î or chd1Î mutations in all combinations. We measured gene activity by ChIP-seq for the Rpb3 subunit of RNA polymerase II for some of these mutants.
2016-02-17 | E-GEOD-69400 | 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:Arrays of regularly spaced nucleosomes dominate chromatin and are often phased, i.e., aligned at reference sites like active promoters. How distances between nucleosomes and distances between phasing sites and nucleosomes are determined remained unclear, specifically, the role of ATP dependent chromatin remodelers in it. Here, we used a genome-wide reconstitution system to probe how yeast remodelers generate phased nucleosome arrays. We find that remodelers bear a structural element named the ‘ruler’ that sets nucleosome spacing, in the order Chd1 < ISW1a < ISW2 < INO80. Structure-based mutagenesis confirmed the functional significance of the ruler element in INO80. Differences in the ruler elements of different remodelers explain the observed nucleosome array features. More generally, we propose that remodelers use their rulers to regulate the direction of nucleosome sliding in response to nucleosome density and environment, leading to nucleosome positioning relative to other nucleosomes, DNA bound factors or DNA sequence elements.
2020-02-10 | GSE140614 | GEO
Project description:The positioning of nucleosomes within the coding regions of eukaryotic genes is aligned with respect to transcriptional start sites. This organization is likely to influence many genetic processes, requiring access to the underlying DNA. Here we show that the combined action of Isw1 and Chd1 nucleosome spacing enzymes is required to maintain this organization. In the absence of these enzymes regular positioning of the majority of nucleosomes is lost. Exceptions include the region upstream of the promoter, the +1 nucleosome and a subset of locations distributed throughout coding regions where other factors are likely to be involved. These observations indicated that ATP-dependent remodeling enzymes are responsible for directing the positioning of the majority of nucleosomes within the Saccharomyces cerevisiae genome. Examination of nucleosome positioning in mutants of snf2-related enzymes Other data used in this study are provided in GEO Series GSE31301 and GSE31833.
2011-09-16 | E-GEOD-31015 | biostudies-arrayexpress
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:Eukaryotic chromosomes are composed of chromatin, in which regularly spaced nucleosomes containing ~147 bp of DNA are separated by linker DNA. Most eukaryotic cells have a characteristic average nucleosome spacing of ~190 bp, corresponding to a ~45 bp linker. However, cortical neurons have a shorter average spacing of ~165 bp. The significance of this atypical global chromatin organization is unclear. We have compared the chromatin structures of purified mouse dorsal root ganglia (DRG) neurons, cortical oligodendrocyte precursor cells (OPCs) and cortical astrocytes. DRG neurons have short average spacing (~165 bp), whereas OPCs (~182 bp) and astrocytes (~183 bp) have longer spacing. We measured nucleosome positions by MNase-seq and gene expression by RNA-seq. Most genes in all three cell types have a promoter chromatin organization typical of active genes: a nucleosome-depleted region at the promoter flanked by regularly spaced nucleosomes phased relative to the transcription start site. In DRG neurons, the spacing of phased nucleosomes downstream of promoters (~178 bp) is longer than expected from the genomic average, whereas phased nucleosome spacing in OPCs and astrocytes is similar to the global average (~183 bp). Thus, the atypical nucleosome spacing of neuronal chromatin does not extend to promoter-proximal regions.
2019-10-07 | GSE133966 | GEO
Project description:Eukaryotic chromosomes are composed of chromatin, in which regularly spaced nucleosomes containing ~147 bp of DNA are separated by linker DNA. Most eukaryotic cells have a characteristic average nucleosome spacing of ~190 bp, corresponding to a ~45 bp linker. However, cortical neurons have a shorter average spacing of ~165 bp. The significance of this atypical global chromatin organization is unclear. We have compared the chromatin structures of purified mouse dorsal root ganglia (DRG) neurons, cortical oligodendrocyte precursor cells (OPCs) and cortical astrocytes. DRG neurons have short average spacing (~165 bp), whereas OPCs (~182 bp) and astrocytes (~183 bp) have longer spacing. We measured nucleosome positions by MNase-seq and gene expression by RNA-seq. Most genes in all three cell types have a promoter chromatin organization typical of active genes: a nucleosome-depleted region at the promoter flanked by regularly spaced nucleosomes phased relative to the transcription start site. In DRG neurons, the spacing of phased nucleosomes downstream of promoters (~178 bp) is longer than expected from the genomic average, whereas phased nucleosome spacing in OPCs and astrocytes is similar to the global average (~183 bp). Thus, the atypical nucleosome spacing of neuronal chromatin does not extend to promoter-proximal regions.
2019-10-07 | GSE133745 | GEO
Project description:The positioning of nucleosomes within the coding regions of eukaryotic genes is aligned with respect to transcriptional start sites. This organization is likely to influence many genetic processes, requiring access to the underlying DNA. Here we show that the combined action of Isw1 and Chd1 nucleosome spacing enzymes is required to maintain this organization. In the absence of these enzymes regular positioning of the majority of nucleosomes is lost. Exceptions include the region upstream of the promoter, the +1 nucleosome and a subset of locations distributed throughout coding regions where other factors are likely to be involved. These observations indicated that ATP-dependent remodeling enzymes are responsible for directing the positioning of the majority of nucleosomes within the Saccharomyces cerevisiae genome. Agilent two-color experiment,Organism: Saccharomyces cerevisiae ,Slides: Agilent Gene Expression S. cerevisiae 8x15k array AMADID: 016333, Labeling kit: Agilent’s Quick-Amp labeling Kit (p/n5190-0444)Method: T7 promoter based-linear amplification to generate labeled complementary RNA.
2011-09-01 | E-GEOD-31833 | biostudies-arrayexpress
Project description:The positioning of nucleosomes within the coding regions of eukaryotic genes is aligned with respect to transcriptional start sites. This organization is likely to influence many genetic processes, requiring access to the underlying DNA. Here we show that the combined action of Isw1 and Chd1 nucleosome spacing enzymes is required to maintain this organization. In the absence of these enzymes regular positioning of the majority of nucleosomes is lost. Exceptions include the region upstream of the promoter, the +1 nucleosome and a subset of locations distributed throughout coding regions where other factors are likely to be involved. These observations indicated that ATP-dependent remodeling enzymes are responsible for directing the positioning of the majority of nucleosomes within the Saccharomyces cerevisiae genome.
2011-09-16 | GSE31015 | GEO