Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Remodelers organize cellular chromatin by counteracting intrinsic histone-DNA sequence preferences in a class-specific manner

ABSTRACT: We assessed the interplay between DNA sequences and ATP-dependent chromatin remodelers in defining the nucleosomal organization of the eukaryotic genome. We compared the genome-wide distribution and impact on chromatin of NURD, (P)BAP, INO80 and ISWI representing four major families of Drosophila remodelers. Each remodeler has a unique set of genomic targets, and generates distinct chromatin signatures. Remodeler loci have characteristic DNA sequence features, predicted to influence nucleosome formation. Strikingly, remodelers counteract DNA sequence-driven nucleosome distribution in two ways: NURD, (P)BAP and INO80 increase histone density at their target sequences, which disfavor positioned nucleosome formation. In contrast, ISWI promotes open chromatin at sites that are propitious for precise nucleosome placement. Thus, both selective targeting and distinct mechanisms of remodeling underlie the functional differentiation of remodelers. We conclude that chromatin organization involves a class-specific antagonism between remodeler activity and DNA sequence-driven nucleosome placement. The supplementary bed files (P)BAP_sites.bed, NURD_sites.bed, INO80_sites.bed, ISWI_sites.bed contain high quality binding sites for each remodeler obtained by intersecting the sets of significant ChIP-chip peaks for each antibody.

ORGANISM(S): Drosophila melanogaster

PROVIDER: GSE32404 | GEO | 2011/12/12

SECONDARY ACCESSION(S): PRJNA146395

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Dynamics of yeast ISWI and CHD chromatin remodeler genomic association (part 1)

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

Dynamics of yeast ISWI and CHD chromatin remodeler genomic association (part 2)

2013-03-01 | E-GEOD-39431 | biostudies-arrayexpress

Genome information processing by the INO80 chromatin remodeler positions nucleosomes

Project description:The mechanistics by which ATP-dependent chromatin remodelers process (epi)genetic information to generate hallmark features of chromatin are fundamental for genome regulation. Here, we advance whole-genome reconstitutions into a fully definable, recombinant approach for probing how remodelers determine nucleosome positioning. Using wild type and structure-guided mutant versions of the Saccharomyces cerevisiae 15-subunit INO80 remodeler, we show that INO80-intrinsic nucleosome positioning relies on direct DNA shape read-out. This requires especially the interplay between the INO80 nuclear actin and core modules, to a lesser extent the HMG-box Nhp10 module and not histone modifications/variants or the Rvb1/2 AAA+-ATPase activity. Extrinsically, nucleosome positioning is guided by the barrier Reb1 via Ino80 ATPase activity modulation or by mere DNA double strand breaks. Taken together, we present a defined and unbiased approach to understand remodeler-mediated nucleosome positioning and delineate how INO80 processes genomic information into nucleosome positioning.

2020-04-30 | GSE145093 | GEO

Expansion of the ISWI chromatin remodeler family with new active complexes

Project description:ISWI chromatin remodelers mobilize nucleosomes to control DNA accessibility. Complexes isolated to date pair one of six regulatory subunits with one of two highly similar ATPases. However, we find that each endogenously expressed ATPase copurifies with every regulatory subunit, substantially increasing the diversity of ISWI complexes, and we additionally identify BAZ2B as a novel, seventh regulatory subunit. Through reconstitution of catalytically active human ISWI complexes, we demonstrate that the new interactions described here are stable and direct. Finally, we profile the nucleosome remodeling functions of the now expanded family of ISWI chromatin remodelers. By revealing the combinatorial nature of ISWI complexes, we provide a basis for better understanding ISWI function in normal settings and disease.

2017-06-03 | MSV000081134 | MassIVE

Ruler elements in chromatin remodelers set nucleosome array spacing and phasing

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

Nucleosome recognition and DNA distortion by the Chd1 remodeler revealed at 2.6 Å resolution

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

Stepwise reconstitution of genomic nucleosome organization with pure proteins

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

Effects of MBD3 depletion on nucleosome occupancy in MCF-7 cells

Project description:We and others have identified that MBD3/NuRD localizes at active promoters and enhancers, suggesting an active role of NuRD at open chromatin region. Because NuRD includes nucleosome remodelers, CHD3 and CHD4, we hypothesized that NuRD regulates nucleosome organization at open chromatin region. To test this idea, we performed micrococcal nuclease digestion followed by massively parallel sequencing (MNase-seq) in MBD3 knockdowned MCF-7 cells. We observed the decrease of nucleosome occupancy at promoters and enhancers in MBD3 knockdowned cells. Our results suggest a regulatory role of MBD3/NuRD at open chromatin region. Mapped nucleosome positioning in control (shLuc) and MBD3 knockdowned MCF-7 cells, in duplicate.

2013-10-31 | E-GEOD-51097 | biostudies-arrayexpress

In vivo Analysis Reveals that ATP-hydrolysis Couples Remodeling to SWI/SNF Release from Chromatin.

Project description:ATP-dependent chromatin remodelers control the accessibility of genomic DNA through nucleosome mobilization. However, the dynamics of genome exploration by remodelers, and the role of ATP hydrolysis in this process remain unclear. We used live-cell imaging of Drosophila polytene nuclei to monitor Brahma (BRM) remodeler interactions with its chromosomal targets. In parallel, we measured local chromatin condensation and its effect on BRM association. Surprisingly, only a small portion of BRM is bound to chromatin at any given time. BRM binds decondensed chromatin but is excluded from condensed chromatin, limiting its genomic search space. BRM-chromatin interactions are highly dynamic, whereas histone-exchange is limited and much slower. Intriguingly, loss of ATP hydrolysis enhanced chromatin retention and clustering of BRM, which was associated with reduced histone turnover. Thus, ATP hydrolysis couples nucleosome remodeling to remodeler release, driving a continuous transient probing of the genome.

2022-01-20 | PXD025474 | Pride

Transcription start site positioning is not affected by +1 nucleosome depletion

Project description:The relationship between the positioning of nucleosomes and transcription start sites (TSSs) is unclear. Here, we report that deletion of the Fun30 class chromatin remodelers Fft2 and Fft3 leads to depletion of +1 nucleosome occupancy. Strikingly, in the vast majority of cases, this depletion had no impact on the placement of the TSS, favoring a model where TSS placement is primarily DNA sequence-driven.

2018-06-30 | GSE85046 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data