Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA290779 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR2125156.fastq.gz | Fastqsanger.gz | |||
| SRR2125157.fastq.gz | Fastqsanger.gz | |||
| SRR2125158.fastq.gz | Fastqsanger.gz | |||
| SRR2125159.fastq.gz | Fastqsanger.gz |
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Project description:CTCF/cohesin play a central role in insulator function and higher-order chromatin organization of mammalian genomes. Recent studies identified a correlation between the orientation of CTCF-binding sites (CBSs) and chromatin loops. To test the functional significance of this observation, we combined CRISPR/Cas9-based genomic-DNA-fragment editing with chromosome-conformation-capture experiments to show that the location and relative orientations of CBSs determine the specificity of long-range chromatin looping in mammalian genomes, using protocadherin (Pcdh) and β-globin as model genes. Inversion of CBS elements within the Pcdh enhancer reconfigures the topology of chromatin loops between the distal enhancer and target promoters, and alters gene-expression patterns. Thus, although enhancers can function in an orientation-independent manner in reporter assays, in the native chromosome context the orientation of at least some enhancers carrying CBSs can determine both the architecture of topological chromatin domains and enhancer/promoter specificity. The findings reveal how 3D chromosome architecture can be encoded by genome sequence.
2015-08-13 | GSE71275 | GEO
Project description:<p>Metabolic lesions with pleiotropic effects on epigenetic regulation and other cellular processes are widely implicated in cancer, yet their oncogenic mechanisms remain poorly understood. Succinate dehydrogenase (SDH) deficiency causes a subset of gastrointestinal stromal tumors (GISTs) with DNA hyper-methylation. Here we associate this hyper-methylation with changes in chromosome topology that activate oncogenic programs. To investigate epigenetic alterations in this disease, we systematically mapped DNA methylation, CTCF insulators, enhancers and chromosome topology in KIT-mutant, PDGFRA-mutant and SDH-deficient GISTs. Although these respective subtypes share similar enhancer landscapes, we identified hundreds of putative insulators where DNA methylation replaced CTCF binding in SDH-deficient GISTs. We focused on disrupted insulators that partitions super-enhancers from FGF3, FGF4 and the KIT oncogene. Recurrent loss of this insulator alters locus topology in SDH-deficient GISTs, allowing aberrant physical interaction between enhancers and oncogenes. CRISPR-mediated excision of the corresponding CTCF motif in an SDH-intact model disrupted the boundary and up-regulated FGFs and KIT expression. Our findings reveal how a metabolic lesion destabilizes chromatin structure to facilitate the initiation and selection of epigenetic alterations that drive oncogenic programs in the absence of canonical mutations.</p>
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Project description:To understand how chromatin domains coordinate gene expression, we dissected select genetic elements organizing topology and transcription around the Prdm14 super enhancer in mouse embryonic stem cells. Taking advantage of allelic polymorphisms, we developed methods to sensitively analyze changes in chromatin topology, gene expression, and protein recruitment. We show that enhancer insulation does not strictly rely on loop formation between its flanking boundaries, that the enhancer activates the Slco5a1 gene beyond its prominent domain boundary, and that it recruits cohesin for loop extrusion. Upon boundary inversion, we find that oppositely-oriented CTCF terminates extrusion trajectories but does not stall cohesin, while deleted or mutated CTCF sites allow cohesin to extend its trajectory. Enhancer-mediated gene activation occurs independent of paused loop extrusion near the gene promoter. We expand upon the loop extrusion model to propose that cohesin loading and extrusion trajectories originating at an enhancer contribute to gene activation.
2021-06-30 | GSE173354 | GEO
Project description:Aberrant activation of the TAL1 oncogene is associated with up to 60% of T-ALL patients and is involved in CTCF mediated genome organization within the TAL1 locus, suggesting the importance of the CTCF boundary in the molecular pathogenesis of T-ALL. Here, we show that deletion of CTCF binding site (CBS) or alternation of CTCF boundary orientation alters expression of the TAL1 oncogene in a cell context dependent manner. Deletion of the CTCF binding site located at -31 Kb upstream of TAL1 (-31CBS) reduces chromatin accessibility in the +51 enhancer and the TAL1 promoter I, and blocks long-range interaction between the +51 erythroid enhancer and TAL1 promoter 1b that inhibits expression of TAL1 in erythroid cells, but not in T-ALL cells. However, in the TAL1 expressed T-ALL primary patient samples or cell line, the T-ALL prone TAL1 promoter IV specifically interacts with the +19 stem cell enhancer that is located 19 kb downstream of the TAL1 promoter and required for TAL1 transcription in the hematopoietic stem cell (HSC) stage. Inversion of -31CBS orientation, but not deletion of -31CBS, alters chromatin accessibility, enhancer/promoter histone modifications, CTCF-mediated topological associated domain (TAD), and enhancer/promoter interaction in the TAL1 locus leading to inhibition of TAL1 oncogene expression and TAL1-driven T cell leukemogenesis. Thus, our data reveal that the TAL1 +19 stem cell enhancer acts not only as stem cell enhancer, but also as a leukemia specific enhancer to activate the TAL1 oncogene in T-ALL. Manipulation of CTCF defined chromatin boundary can alter TAL1 TAD and oncogenic transcription networks in leukemogenesis.
2020-04-06 | GSE135320 | GEO
Project description:Insulators play a critical role in spatiotemporal gene expression in metazoans by separating active and repressive chromatin domains and preventing inappropriate enhancer-promoter contacts. The evolutionarily conserved CCCTC-binding factor (CTCF) is required for insulator function in mammals, but not all of its binding sites act as insulators. Here, we explore the sequence requirements of CTCF-mediated transcriptional insulation with the use of a sensitive insulator reporter assay in mouse embryonic stem cells. We find that potent insulation is provided by multiple CTCF binding sites. Furthermore, CTCF-mediated insulation is dependent on DNA sequences adjacent to its core binding motifs, and CTCF binding sites from topologically associating domains (TAD) boundaries are more likely to function as insulators than those outside TAD boundaries independent of binding strength. Using chromosomal conformation capture assays and high resolution chromatin imaging techniques, we demonstrate that insulators reduce enhancer-promoter contacts by forming local chromatin domains. Taken together, our results provide strong genetic, molecular and imaging evidence connecting chromatin topology to action of insulators in the mammalian genome.
2020-11-25 | GSE162101 | GEO
Project description:Insulators play a critical role in spatiotemporal gene expression in metazoans by separating active and repressive chromatin domains and preventing inappropriate enhancer-promoter contacts. The evolutionarily conserved CCCTC-binding factor (CTCF) is required for insulator function in mammals, but not all of its binding sites act as insulators. Here, we explore the sequence requirements of CTCF-mediated transcriptional insulation with the use of a sensitive insulator reporter assay in mouse embryonic stem cells. We find that potent insulation is provided by multiple CTCF binding sites. Furthermore, CTCF-mediated insulation is dependent on DNA sequences adjacent to its core binding motifs, and CTCF binding sites from topologically associating domains (TAD) boundaries are more likely to function as insulators than those outside TAD boundaries independent of binding strength. Using chromosomal conformation capture assays and high resolution chromatin imaging techniques, we demonstrate that insulators reduce enhancer-promoter contacts by forming local chromatin domains. Taken together, our results provide strong genetic, molecular and imaging evidence connecting chromatin topology to action of insulators in the mammalian genome.
2020-07-06 | GSE153402 | GEO
Project description:Insulators play a critical role in spatiotemporal gene expression in metazoans by separating active and repressive chromatin domains and preventing inappropriate enhancer-promoter contacts. The evolutionarily conserved CCCTC-binding factor (CTCF) is required for insulator function in mammals, but not all of its binding sites act as insulators. Here, we explore the sequence requirements of CTCF-mediated transcriptional insulation with the use of a sensitive insulator reporter assay in mouse embryonic stem cells. We find that potent insulation is provided by multiple CTCF binding sites. Furthermore, CTCF-mediated insulation is dependent on DNA sequences adjacent to its core binding motifs, and CTCF binding sites from topologically associating domains (TAD) boundaries are more likely to function as insulators than those outside TAD boundaries independent of binding strength. Using chromosomal conformation capture assays and high resolution chromatin imaging techniques, we demonstrate that insulators reduce enhancer-promoter contacts by forming local chromatin domains. Taken together, our results provide strong genetic, molecular and imaging evidence connecting chromatin topology to action of insulators in the mammalian genome.
2020-07-06 | GSE153400 | GEO
Project description:Gain-of-function IDH mutations define major clinical and prognostic classes of gliomas. Mutant IDH protein produces a novel onco-metabolite, 2-hydroxyglutarate (2-HG), that interferes with iron-dependent hydroxylase enzymes, including the TET family of 5'-methylcytosine hydroxylases. TET enzymes are critical for the dynamic regulation of DNA methylation. IDH mutant gliomas thus manifest a CpG island methylator phenotype (G-CIMP), though the functional significance of this altered epigenetic state remains unclear. Here we show that IDH1 mutant gliomas exhibit hyper-methylation at CTCF binding sites, leading to reduced binding of this methylation-sensitive insulator protein. Loss of CTCF binding is associated with a loss of insulation between topological domains and aberrant gene activation. We specifically demonstrate that loss of CTCF at a domain boundary permits a constitutive enhancer to aberrantly interact with the receptor tyrosine kinase gene PDGFRA, a prominent glioma oncogene. Treatment of IDH mutant gliomaspheres with demethylating agent partially restores insulator function and reduces PDGFRA expression. Conversely, CRISPR-mediated disruption of the CTCF binding sequence in IDH wildtype gliomaspheres induces PDGFRA expression and increases proliferation. Our study suggests that IDH mutations promote gliomagenesis by disrupting chromosomal topology and allowing aberrant regulatory interactions that induce oncogene expression. CTCF occupancy characterization and histone H3K27 acetylation profiling in IDH1 mutant and wild-type glioma patient specimens and culture models. ChIP-seq raw data is to be made available through dbGaP (controlled access) due to patient privacy concerns.
2015-12-23 | E-GEOD-70991 | biostudies-arrayexpress
Project description:Deletion of CTCF sites in the SHH-LMBR1 locus alters enhancer-promoter interaction and leads to acheiropodia
| PRJNA639862 | ENA
Project description:We reconstituted arrays of CTCF binding sites (L1, L2, L3, L4, R1, R2 and R3) and devised a synthetic topological insulator with tetO for chromatin-engineering (STITCH). By coupling STITCH with tetR linked to the KRAB domain to induce heterochromatin and disable the insulation, we developed a drug-inducible system to control gene activation by enhancers. We inserted STITCH into five different positions of the remaining allele of the locus: \\"STITCH+30kb\\", \\"STITCH+440kb\\", \\"STITCH+1760kb\\" and \\"STITCH+1790kb\\" have the STITCH insertions away from the MYC promoter for the indicated distances to the telomeric side of the p arm of the chromosome. \\"STITCH-30kb\\", at the 30-kb upstream from the MYC. We also made a deletion clone of the enhancer region, termed del(30-440). We made deletion of each CTCF array, L (delL) and R (delR), inversion of R (invR), deletion of the middle five binding sites from L2 to R2 (del(L2-R2)), and deletion of the six sites but for R3 (del(L1-R2)) in STITCH+30kb. We also obtained deletion and inversion of the whole of STITCH (del(L1-R3) and inv(L1-R3)). We integrated a transgene consisting of tetR-KRAB followed by DNA encoding the 2A peptide and the puromycin resistant gene with piggyBac transposition into the genome in the STITCH+30kb clone (STITCH/KRAB). We performed 4C-seq (Circular chromatin conformation capture assay followed by deep-sequencing) from the MYC promoter as a viewpoint to see how STITCH impacts on the chromatin conformation.
2020-05-01 | E-MTAB-7668 | biostudies-arrayexpress