The single-molecule accessibility landscape of newly replicated mammalian chromatin
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ABSTRACT:
ORGANISM(S): Mus musculus Homo sapiens
PROVIDER: GSE245558 | GEO | 2024/11/12
REPOSITORIES: GEO
Similar Datasets
Project description:The single-molecule accessibility landscape of newly replicated mammalian chromatin
| PRJNA1032606 | ENA
Project description:Catalytic activity of the ISWI family of remodelers is critical for nucleosomal organization and transcription factor binding, including the insulator protein CTCF. To define which subcomplex mediates these diverse functions we phenotyped a panel of isogenic mouse stem cell lines each lacking one of six ISWI accessory subunits. Individual deletions of either CERF, RSF1, ACF, WICH or NoRC subcomplexes only moderately affect the chromatin landscape, while removal of the NURF-specific subunit BPTF leads to drastic reduction in chromatin accessibility and Snf2h ATPase localization around CTCF sites. While this reduces distances to the adjacent nucleosomes it only modestly impacts CTCF binding itself. In absence of accessibility, the insulator function of CTCF is nevertheless impaired resulting in lower occupancy of cohesin and cohesin-loading factors, and reduced insulation at these sites, highlighting the need of NURF-mediated remodeling for open chromatin and proper CTCF function. Our comprehensive analysis reveals a specific role for NURF in mediating Snf2h localization and chromatin opening at bound CTCF sites showing that local accessibility is critical for cohesin binding and insulator function.
2024-03-13 | PXD042945 | Pride
Project description:The transcription factor CTCF appears indispensable in defining topologically associated domain boundaries and maintaining chromatin loop structures within these domains, supported by numerous functional studies. However, acute depletion of CTCF globally reduces chromatin interactions but does not significantly alter transcription. Here we systematically integrated multi-omics data including ATAC-seq, RNA-seq, WGBS, Hi-C, Cut&Run, CRISPR-Cas9 survival dropout screening, time-solved deep proteomic and phosphoproteomic analyses in cells carrying auxin-induced degron at endogenous CTCF locus. Acute CTCF protein degradation markedly rewired genome-wide chromatin accessibility. Increased accessible chromatin regions were largely located adjacent to CTCF-binding sites at promoter regions and insulator sites and were associated with enhanced transcription of nearby genes. In addition, we used CTCF-associated multi-omics data to establish a combinatorial data analysis pipeline to discover CTCF co-regulatory partners in regulating downstream gene expression. We successfully identified 40 candidates, including multiple established partners (i.e., MYC) supported by all layers of evidence. Interestingly, many CTCF co-regulators (e.g., YY1, ZBTB7A) that have evident alterations of respective downstream gene expression do not show changes at their expression levels across the multi-omics measurements upon acute CTCF loss, highlighting the strength of our system to discover hidden co-regulatory partners associated with CTCF-mediated transcription. This study highlights CTCF loss rewires genome-wide chromatin accessibility, which plays a critical role in transcriptional regulation
2021-07-04 | PXD026484 | Pride
Project description:Replication of the eukaryotic genome occurs in the context of chromatin, a nucleoprotein packaging state consisting of repeating nucleosomes. Chromatin is commonly thought to carry epigenetic information from one generation to the next, although it is unclear how such information survives the disruptions of nucleosomal architecture that occur during genomic replication. Here, we sought to directly measure a key aspect of chromatin structure dynamics during replication â how rapidly nucleosome positions are established on the newly-replicated daughter genomes. By isolating newly-synthesized DNA marked with the nucleotide analogue EdU, we characterize nucleosome positions on both daughter genomes of budding yeast during a time course of chromatin maturation. We find that nucleosomes rapidly adopt their mid log positions at highly-transcribed genes, and that this process was impaired upon treatment with the transcription inhibitor thiolutin, consistent with a role for transcription in positioning nucleosomes in vivo. Additionally, experiments in the Hir1Î background reveal a role for HIR in nucleosome spacing. Using strand-specific EdU libraries, we characterize nucleosome positions on the leading and lagging strand daughter genomes, uncovering differences in chromatin maturation dynamics between the two daughter genomes at hundreds of genes. Our data define the maturation dynamics of newly-replicated chromatin, and support a role for transcription in sculpting the chromatin template. We have mapped changes in nucleosome positions on newly replicated DNA in a timecourse after genome replication. We have used Micrococcal Nuclease footprinting of cross linked chromatin to determine nucleosome positions and EdU (ethylene deoxy uridine) to mark nascent DNA strands. EdU incorporated into nascent DNA strands was biotinylated with Click chemistry and nascent DNA strand fragments were subsequently isolated using Streptavidin coated magnetic beads.
2016-08-25 | E-GEOD-74090 | biostudies-arrayexpress
Project description:Chromatin features are thought to have a role in the epigenetic transmission of transcription states from one cell generation to the next. It is unclear how chromatin structure survives disruptions caused by genomic replication or if chromatin features are instructive of the transcription state of the underlying gene. We developed a method to monitor budding yeast replication, transcription and chromatin maturation dynamics on each daughter genome in parallel, with which we identified clusters of secondary origins surrounding known origins. We find a difference in the timing of lagging and leading strand replication on the order of minutes at most yeast genes. We propose a model in which the majority of old histones and RNAPII bind to the gene copy that replicated first, while newly synthesized nucleosomes are assembled on the copy that replicated second. RNAPII enrichment then shifts to the sister copy that replicated second. The order of replication is largely determined by genic orientation: if transcription and replication are co-directional the leading strand replicates first; if they are counter-directional the lagging strand replicates first. A mutation in the Mcm2 subunit of the replicative helicase Mcm2-7 which impairs Mcm2 interactions with histone H3 slows down replication forks but does not qualitatively change the asymmetry in nucleosome distribution observed in the WT. Active transcription states are inherited simultaneously and independently of their underlying chromatin states through the recycling of the transcription machinery and old histones, respectively. Transcription thus actively contributes to the reestablishment of the active chromatin state.
2021-12-18 | GSE160507 | GEO
Project description:Chromatin features are thought to have a role in the epigenetic transmission of transcription states from one cell generation to the next. It is unclear how chromatin structure survives disruptions caused by genomic replication or if chromatin features are instructive of the transcription state of the underlying gene. We developed a method to monitor budding yeast replication, transcription and chromatin maturation dynamics on each daughter genome in parallel, with which we identified clusters of secondary origins surrounding known origins. We find a difference in the timing of lagging and leading strand replication on the order of minutes at most yeast genes. We propose a model in which the majority of old histones and RNAPII bind to the gene copy that replicated first, while newly synthesized nucleosomes are assembled on the copy that replicated second. RNAPII enrichment then shifts to the sister copy that replicated second. The order of replication is largely determined by genic orientation: if transcription and replication are co-directional the leading strand replicates first; if they are counter-directional the lagging strand replicates first. A mutation in the Mcm2 subunit of the replicative helicase Mcm2-7 which impairs Mcm2 interactions with histone H3 slows down replication forks but does not qualitatively change the asymmetry in nucleosome distribution observed in the WT. Active transcription states are inherited simultaneously and independently of their underlying chromatin states through the recycling of the transcription machinery and old histones, respectively. Transcription thus actively contributes to the reestablishment of the active chromatin state.
2021-12-18 | GSE160265 | GEO
Project description:Chromatin features are thought to have a role in the epigenetic transmission of transcription states from one cell generation to the next. It is unclear how chromatin structure survives disruptions caused by genomic replication or if chromatin features are instructive of the transcription state of the underlying gene. We developed a method to monitor budding yeast replication, transcription and chromatin maturation dynamics on each daughter genome in parallel, with which we identified clusters of secondary origins surrounding known origins. We find a difference in the timing of lagging and leading strand replication on the order of minutes at most yeast genes. We propose a model in which the majority of old histones and RNAPII bind to the gene copy that replicated first, while newly synthesized nucleosomes are assembled on the copy that replicated second. RNAPII enrichment then shifts to the sister copy that replicated second. The order of replication is largely determined by genic orientation: if transcription and replication are co-directional the leading strand replicates first; if they are counter-directional the lagging strand replicates first. A mutation in the Mcm2 subunit of the replicative helicase Mcm2-7 which impairs Mcm2 interactions with histone H3 slows down replication forks but does not qualitatively change the asymmetry in nucleosome distribution observed in the WT. Active transcription states are inherited simultaneously and independently of their underlying chromatin states through the recycling of the transcription machinery and old histones, respectively. Transcription thus actively contributes to the reestablishment of the active chromatin state.
2021-12-18 | GSE160262 | GEO
Project description:Faithful DNA replication is essential for normal cell division and differentiation. In eukaryotic cells, DNA replication takes place on chromatin. This poses the critical question as to how DNA replication can progress through chromatin, which is inhibitory to all DNA-dependent processes. Here, we have developed a novel genome-wide method to measure chromatin accessibility to micrococcal nuclease that is normalized for nucleosome density, NCAM (Normalized Chromatin Accessibility to MNase) assay. This method enabled us to discover that chromatin accessibility increases specifically at and ahead of DNA replication forks in normal S phase and during replication stress. We further found that Mec1, a key regulatory ATR-like kinase in the S-phase checkpoint, is required for both normal chromatin accessibility around replication forks and replication fork rate during replication stress. In this study we sought to analyze the chromatin structural changes that take place at sites of DNA replication. To this end, we obtained yeast cell populations synchronously undergoing DNA replication by M-NM-1-factor G1 arrest and release. In order to analyze chromatin structure at sites of DNA replication we first mapped the genomic locations undergoing DNA replication to high-resolution, strand-specific microarrays tiling chromosomes III, VI, and XII, covering ~14% of the genome. Two complementary approaches were taken: (1) we mapped fork positions by chromatin immunoprecipitation (ChIP) of a FLAG-tagged DNA polymerase 1 (Pol1), a replication fork component and (2) we mapped the sites of active DNA synthesis by generating DNA copy number profiles. We then analyzed chromatin structure at the sites of DNA replication by Micrococcal nuclease mononucleosome mapping and by generating histone H3 density maps. We further generated a Normalized Chromatin Accessibility to MNase (NCAM) signal by normalizing MNase mononucleosome signal for histone H3 density. NCAM signal represents a measure of nucleosome accessibility to MNase that is normalized for nucleosome content. These three approaches allowed us to assess potential changes in nucleosome positioning, nucleosome density, and nucleosome accessibility during DNA replication. We searched for changes in chromatin structure by comparing, during S phase, regions undergoing DNA replication to those not yet replicated, and also by comparing the same region before replication (not replicated, G1 arrested control) and during DNA replication in S phase. We typically harvested S phase cells at 30 or 60 minutes after release from G1 arrest. Experimental conditions included releasing cells into rich media at 24M-BM-0C or into rich media containing 200 mM Hydroxyurea (HU). Both conditions slowed down replication fork rate and made these experiments feasible. For each strain, samples for the different experiments (Chromatin for Pol1 and H3 ChIP, in vivo MNase digestion, and DNA for DNA copy number profiles) were harvested simultaneously for each time point. Therefore, comparisons between time points for each strain must be made using samples from the same replicate experiment. Our analysis included WT cells, as well as S phase checkpoint mutants (M-NM-^Tmec1 M-NM-^Tsml1 and mec1-100 M-NM-^Tsml1), as well as control strains (M-NM-^Tsml1).
2013-01-17 | E-GEOD-43548 | biostudies-arrayexpress
Project description:Chromatin organization must be maintained during cell proliferation to preserve cellular identity and genome integrity. However, DNA replication results in transient displacement of DNA bound proteins, and it is unclear how they regain access to newly replicated DNA. Using quantitative MS-based proteomics coupled to Nascent Chromatin Capture, we provide time resolved binding kinetics for thousands of proteins behind replisomes of mid-S replicated regions. This shows that most proteins regain access within the first 15 minutes after the passage of the fork. In contrast, 25% of the identified proteins do not, and this delay cannot be inferred from their known function, physicochemical properties, or nuclear abundance. Here, we provide data where we impaired the H3K27me3 restoration to analyse its impact into chromatin restoration. To this aim, we used the EPZ-6438 inhibitor, which blocks the histone methyltransferase EZH2. Two time-points are analysed by NCC along the cell cycle in late replicated regions: nascent chromatin, just after the passage of the fork, and a sample 16 hours later, in late G1 phase. Our data support that H3K27me3 have an important role in chromatin restoration. Data available in this entry are related with the supplementary table 6 from our manuscript.
2023-02-02 | PXD038376 | Pride
Project description:We report the application of high through-put tag sequencing to measure the location and strand of DNA embedded ribonucleotides in the yeast genome. Mutations in the catalytic subunits of the polymerases (pol1-L868M, pol2-M644G and pol3-L612M) lead to the increased incorporation of ribonucleotides during DNA replication, providing an in vivo label with which to track the contribution of each polymerase to the fully replicated genome. Yeast strains used in this study are deleted for rnh201, encoding the catalytic subunit of the RNase H2 gene so that embedded ribonucleotides are not rapidly removed by ribonucleotide excision repair following DNA replication. Analysis of this data demonstrates that polymerase alpha contributes to the fully replicated genome.
2015-01-26 | GSE64521 | GEO