CRISPR-mediated deletion of prostate cancer risk-associated CTCF loop anchors identifies repressive chromatin loops
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ABSTRACT:
PROVIDER: PRJNA485892 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR7691802.fastq.gz | Fastqsanger.gz | |||
| SRR7751530.fastq.gz | Fastqsanger.gz | |||
| SRR7751540.fastq.gz | Fastqsanger.gz | |||
| SRR7751550.fastq.gz | Fastqsanger.gz | |||
| SRR7751531.fastq.gz | Fastqsanger.gz |
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Project description:Background: Recent genome-wide association studies (GWAS) have identified more than 100 loci associated with increased risk of prostate cancer, most of which are in non-coding regions of the genome. Understanding the function of these non-coding risk loci is critical to elucidate the genetic susceptibility to prostate cancer. Results: We generated genome-wide regulatory element maps and performed genome-wide chromosome confirmation capture assays (in situ Hi-C) in normal and tumorigenic prostate cells. Using this information, we annotated the regulatory potential of 2,181 fine-mapped PCa risk-associated SNPs and predicted a set of target genes that are regulated by PCa risk-related H3K27Ac-mediated loops. We next identified PCa risk-associated CTCF sites involved in long-range chromatin loops. We used CRISPR-mediated deletion to remove PCa risk-associated CTCF anchor regions and the CTCF anchor regions looped to the PCa risk-associated CTCF sites; we observed up to 100 fold increases in expression of genes within the loops when the PCa risk-associated CTCF anchor regions were deleted. Conclusions: We have identified GWAS risk loci involved in long-range loops that function to repress gene expression within chromatin loops. Our studies provide new insights into the genetic susceptibility to prostate cancer.
2018-08-15 | GSE118514 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below, and presents the high throuput sequencing datasets that were generated as part of a larger study that investigates the role of CTCF and cohesin as key drivers of 3D-nuclear organization, anchoring the megabase-scale Topologically Associating Domains (TADs) that segment the genome. This study presents and validates a computational method to predict cohesin-and-CTCF binding sites that form intra-TAD DNA loops. The intra-TAD loop anchors identified are structurally indistinguishable from TAD anchors regarding binding partners, sequence conservation, and resistance to cohesin knockdown; further, the intra-TAD loops retain key functional features of TADs, including chromatin contact insulation, blockage of repressive histone mark spread, and ubiquity across tissues. The intra-TAD loops are proposed to be formed by the same loop extrusion mechanism as the larger TAD loops; their shorter length enables finer regulatory control in restricting enhancer-promoter interactions, which enables selective, high-level expression of gene targets of super-enhancers and genes located within repressive nuclear compartments. These findings elucidate the role of intra-TAD cohesin-and-CTCF binding in nuclear organization associated with widespread insulation of distal enhancer activity.
2018-05-11 | GSE102999 | GEO
Project description:BackgroundRecent genome-wide association studies (GWAS) have identified more than 100 loci associated with increased risk of prostate cancer, most of which are in non-coding regions of the genome. Understanding the function of these non-coding risk loci is critical to elucidate the genetic susceptibility to prostate cancer.ResultsWe generate genome-wide regulatory element maps and performed genome-wide chromosome confirmation capture assays (in situ Hi-C) in normal and tumorigenic prostate cells. Using this information, we annotate the regulatory potential of 2,181 fine-mapped prostate cancer risk-associated SNPs and predict a set of target genes that are regulated by prostate cancer risk-related H3K27Ac-mediated loops. We next identify prostate cancer risk-associated CTCF sites involved in long-range chromatin loops. We use CRISPR-mediated deletion to remove prostate cancer risk-associated CTCF anchor regions and the CTCF anchor regions looped to the prostate cancer risk-associated CTCF sites, and we observe up to 100-fold increases in expression of genes within the loops when the prostate cancer risk-associated CTCF anchor regions are deleted.ConclusionsWe identify GWAS risk loci involved in long-range loops that function to repress gene expression within chromatin loops. Our studies provide new insights into the genetic susceptibility to prostate cancer.
| S-EPMC6176514 | biostudies-literature
Project description:Polycomb Repressive Complex 1 (PRC1) and CCCTC-binding factor (CTCF) are critical regulators of 3D chromatin architecture that influence cellular transcriptional programs. Spatial chromatin structures comprise conserved compartments, topologically associating domains (TADs), and dynamic, cell-type-specific chromatin loops. Although the role of CTCF in chromatin organization is well-known, the involvement of PRC1 is less understood. In this study, we identified an unexpected, essential role for the canonical Pcgf2-containing PRC1 complex (cPRC1.2), a known transcriptional repressor, in activating bivalent genes during differentiation. Our Hi-C analysis revealed that cPRC1.2 forms chromatin loops at bivalent promoters, rendering them silent yet poised for activation. Using mouse embryonic stem cells (ESCs) with CRISPR/Cas9-mediated gene editing, we found that the loss of Pcgf2, though not affecting the global level of H2AK119ub1, disrupts these cPRC1.2 loops in ESCs and impairs the transcriptional induction of crucial target genes necessary for neuronal differentiation. Furthermore, we identified CTCF enrichment at cPRC1.2 loop anchors and at Polycomb group (PcG) bodies, nuclear foci with concentrated PRC1 and its tethered chromatin domains, suggesting that PRC1 and CTCF cooperatively shape chromatin loop structures. Through virtual 4C and other genomic analyses, we discovered that establishing neuronal progenitor cell (NPC) identity involves a switch from cPRC1.2-mediated chromatin loops to CTCF-mediated active loops, enabling the expression of critical lineage-specific factors. This study uncovers a novel mechanism by which pre-formed PRC1 and CTCF loops at lineage-specific genes maintain a poised state for subsequent gene activation, advancing our understanding of the role of chromatin architecture in controlling cell fate transitions.
2025-01-28 | GSE278946 | GEO
Project description:A WIZ/Cohesin/CTCF complex anchors DNA loops to define gene expression and cell identity
| PRJNA565013 | ENA
Project description:We use in situ Hi-C to probe the three-dimensional architecture of genomes, constructing haploid and diploid maps of nine cell types. The densest, in human lymphoblastoid cells, contains 4.9 billion contacts, achieving 1-kilobase resolution. We find that genomes are partitioned into local domains, which are associated with distinct patterns of histone marks and segregate into six subcompartments. We identify ~10,000 loops. These loops frequently link promoters and enhancers, correlate with gene activation, and show conservation across cell types and species. Loop anchors typically occur at domain boundaries and bind CTCF. CTCF sites at loop anchors occur predominantly (>90%) in a convergent orientation, with the asymmetric motifs ‘facing’ one another. The inactive X-chromosome splits into two massive domains and contains large loops anchored at CTCF-binding repeats. in situ Hi-C and dilution Hi-C were used to probe the three-dimensional structure of the genome in eight diverse human cell types and one mouse cell type
2014-12-11 | E-GEOD-63525 | biostudies-arrayexpress
Project description:Identification of genomic anchors across the MHC in untreated MRC5 fibroblasts, and fibroblasts treated with IFN-gamma, using high resolution microarrays. Identification of genomic anchors using MRC5 fibroblasts, and fibroblasts treated with IFN-gamma: Loop associated DNA vs Matrix associated DNA, 2 biological replicates
2012-02-16 | E-GEOD-35845 | biostudies-arrayexpress
Project description:We recently used in situ Hi-C to create kilobase-resolution 3D maps of mammalian genomes. Here, we combine these with new Hi-C, microscopy, and genome-editing experiments to study the physical structure of chromatin fibers, domains, and loops. We find that the observed contact domains are inconsistent with the equilibrium state for an ordinary condensed polymer. Combining Hi-C data and novel mathematical theorems, we show that contact domains are also not consistent with a fractal globule. Instead, we use physical simulations to study two models of genome folding. In one, intermonomer attraction during polymer condensation leads to formation of an anisotropic "tension globule." In the other, CTCF and cohesin act together to extrude loops during interphase. Both models are consistent with the observed contact domains and with the observation that contact domains tend to form inside loops. However, the extrusion model explains a far wider array of observations, such as why loops tend not to overlap and why the CTCF-binding motifs at pairs of loop anchors lie in the convergent orientation. Finally, we perform 13 genome-editing experiments examining the effect of altering CTCF-binding sites on chromatin folding. The convergent rule correctly predicts the affected loop in every case. Moreover, the extrusion model accurately predicts in silico the 3D maps resulting from each experiment using only the location of CTCF-binding sites in the WT. Thus, we show that it is possible to disrupt, restore, and move loops and domains using targeted mutations as small as a single base pair. in situ Hi-C and HYbrid Capture Hi-C (Hi-C2) were used to probe the three-dimensional structure of the genome in two different human cell types before and after genome editing.
2015-10-23 | E-GEOD-74072 | biostudies-arrayexpress
Project description:DNA replication occurs through an intricately regulated series of molecular events and is fundamental for genome stability. It is currently unknown how the location of replication origins is determined in the human genome. Here, we dissect the role for topologically associating domains (TADs), subTADs, and loops in the positioning of replication initiation zones (IZs). We stratify TADs/subTADs by the presence of corner-dots indicative of loops and the orientation of CTCF motifs. We find that high-efficiency, early replicating IZs localize to boundaries between adjacent corner-dot TADs anchored by high-density arrays of divergently and convergently-oriented CTCF motifs. By contrast, low-efficiency IZs localize to weak boundaries devoid of CTCF and corner-dots. Upon ablation of cohesin-mediated loop extrusion in G1, high-efficiency IZs become diffuse and de-localized specifically at boundaries with complex CTCF motif orientation. Moreover, G1 knock-down of the cohesin unloading factor WAPL results in gained long-range loops and narrowed localization of IZs at the same boundaries. Finally, targeted deletion or insertion of specific boundaries causes local replication timing shifts consistent with loss and gain of IZs, respectively. Our data support a model in which cohesin-mediated loop extrusion and stalling at a subset of genetically-encoded TAD/subTAD boundaries is an essential determinant of the precise location of replication initiation in human S phase.
2021-12-05 | GSE190117 | GEO
Project description:Cohesin catalyses the folding of the genome into loops that are anchored by CTCF. The molecular mechanism of how cohesin and CTCF structure the 3D genome has remained unclear. Here we show that a segment within the CTCF N terminus interacts with the SA2-SCC1 subunits of cohesin. A 2.6 Å crystal structure of SA2-SCC1 in complex with CTCF reveals the molecular basis of the interaction. We demonstrate that this interaction is specifically required for CTCF-anchored loops and contributes to the positioning of cohesin at CTCF-binding sites. A similar motif is present in a number of established and novel cohesin ligands, including the cohesin release factor WAPL. Our data suggest that CTCF enables chromatin loop formation by protecting cohesin against loop release. These results provide fundamental insights into the molecular mechanism that enables dynamic regulation of chromatin folding by cohesin and CTCF.
2020-01-07 | GSE126636 | GEO