CTCF-mediated insulation and chromatin environment modulate Car5b escape from X inactivation
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ABSTRACT:
PROVIDER: PRJNA1219595 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR24423385_1.fastq.gz | Fastqsanger.gz | |||
| SRR24423385_2.fastq.gz | Fastqsanger.gz | |||
| SRR24423386_1.fastq.gz | Fastqsanger.gz | |||
| SRR24423386_2.fastq.gz | Fastqsanger.gz | |||
| SRR32246486_1.fastq.gz | Fastqsanger.gz |
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Project description:Although the chromatin regulator CTCF is enriched at genes escaping from X-chromosome inactivation (XCI), molecular mechanisms remain elusive. We examined CTCF and epigenetic features at escape genes on the inactive X (Xi) in mouse F1 hybrid cells and tissues. We found that escape genes are located inside topologically insulated domains limited by convergent arrays of CTCF binding sites, suggesting loop formation. Xi-specific deletion of a CTCF right boundary of the escape gene Car5b caused loss of CTCF binding and changes of histone modifications at Car5b and abolished escape, suggesting loss of insulation. This is consistent with Car5b lack of escape in mouse brain showing no CTCF binding at the boundary. Inversion of this boundary had no effect on Car5b escape, suggesting that tandem coiled looping could still function as insulation. To test whether chromatin features of the Xi could affect escape we examined mutants in which the Xi-specific compact structure is disrupted or there is loss of H3K27me3 enrichment. We found that both conditions cause an Xi-specific increase in active marks and gene expression at escape regions, suggesting that the 3D structure and heterochromatic marks of the Xi play a role in modulating escape levels of genes insulated by CTCF.
2023-05-18 | GSE231626 | GEO
Project description:Although the chromatin regulator CTCF is enriched at genes escaping from X-chromosome inactivation (XCI), molecular mechanisms remain elusive. We examined CTCF and epigenetic features at escape genes on the inactive X (Xi) in mouse F1 hybrid cells and tissues. We found that escape genes are located inside topologically insulated domains limited by convergent arrays of CTCF binding sites, suggesting loop formation. Xi-specific deletion of a CTCF right boundary of the escape gene Car5b caused loss of CTCF binding and changes of histone modifications at Car5b and abolished escape, suggesting loss of insulation. This is consistent with Car5b lack of escape in mouse brain showing no CTCF binding at the boundary. Inversion of this boundary had no effect on Car5b escape, suggesting that tandem coiled looping could still function as insulation. To test whether chromatin features of the Xi could affect escape we examined mutants in which the Xi-specific compact structure is disrupted or there is loss of H3K27me3 enrichment. We found that both conditions cause an Xi-specific increase in active marks and gene expression at escape regions, suggesting that the 3D structure and heterochromatic marks of the Xi play a role in modulating escape levels of genes insulated by CTCF.
2025-02-08 | GSE288844 | GEO
Project description:CTCF-mediated insulation and chromatin environment modulate Car5b escape from X inactivation II
| PRJNA1219604 | ENA
Project description:CTCF-mediated insulation and chromatin environment modulate Car5b escape from X inactivation I
| PRJNA967025 | ENA
Project description:X chromosome inactivation (XCI) silences most genes on one X chromosome in female mammals, but some genes escape XCI. To identify escape gene in vivo and to explore molecular mechanisms that regulate this process we analyzed the allele-specific expression and chromatin structure of X-linked genes in mouse tissues and cells with skewed XCI and distinguishable alleles based on single nucleotide polymorphisms. Using a new method to estimate allelic expression, we demonstrate a continuum between complete silencing and significant expression from the inactive X (Xi). Few genes (2-3%) escape XCI to a significant level and only a minority differs between mouse tissues, suggesting stringent silencing and escape controls. Allelic profiles of DNase I hypersensitivity and RNA polymerase II occupancy of genes on the Xi correlate with escape from XCI. Allelic binding profiles of the DNA binding protein CCCTC-binding factor (CTCF) in different cell types indicate that CTCF binding at the promoter correlates with escape. Importantly, CTCF binding at the boundary between escape and silenced domains may prevent the spreading of active escape chromatin into silenced domains. Examination of CTCF and RNA PolIIS5p occupancy in mouse hybrid cells and adult tissues.
2015-02-20 | E-GEOD-59778 | biostudies-arrayexpress
Project description:X chromosome inactivation (XCI) silences most genes on one X chromosome in female mammals, but some genes escape XCI. To identify escape gene in vivo and to explore molecular mechanisms that regulate this process we analyzed the allele-specific expression and chromatin structure of X-linked genes in mouse tissues and cells with skewed XCI and distinguishable alleles based on single nucleotide polymorphisms. Using a new method to estimate allelic expression, we demonstrate a continuum between complete silencing and significant expression from the inactive X (Xi). Few genes (2-3%) escape XCI to a significant level and only a minority differs between mouse tissues, suggesting stringent silencing and escape controls. Allelic profiles of DNase I hypersensitivity and RNA polymerase II occupancy of genes on the Xi correlate with escape from XCI. Allelic binding profiles of the DNA binding protein CCCTC-binding factor (CTCF) in different cell types indicate that CTCF binding at the promoter correlates with escape. Importantly, CTCF binding at the boundary between escape and silenced domains may prevent the spreading of active escape chromatin into silenced domains. Examination of allelic expression in mouse hybrid tissues.
2015-02-20 | E-GEOD-59777 | biostudies-arrayexpress
Project description:BackgroundGenes that escape X-chromosome inactivation (XCI) in female somatic cells vary in number and levels of escape among mammalian species and tissues, potentially contributing to species- and tissue-specific sex differences. CTCF, a master chromatin conformation regulator, is enriched at escape regions and may play an important role in regulating escape, but the molecular mechanisms remain elusive.ResultsCTCF binding profiles and epigenetic features were systematically examined at escape genes (escapees) using mouse allelic systems with skewed XCI to distinguish the inactive X (Xi) and active X (Xa) chromosomes. We found that six constitutive and two facultative escapees are located inside 30-800 kb domains marked by convergent arrays of CTCF binding sites, consistent with the formation of chromatin loops. Facultative escapees show clear differences in CTCF binding depending on their XCI status in specific cell types/tissues. In addition, sets of strong and in some cases divergent CTCF binding sites located at the boundary between an escapee and its adjacent neighbors subject to XCI would also help insulate domains. Indeed, deletion but not inversion of a CTCF binding site at the boundary between the facultative escapee Car5b and its silent neighbor Siah1b results in a dramatic reduction of Car5b escape. This is associated with reduced CTCF and cohesin binding, which indicates loss of looping and insulation and is supported by 3C combined with Hi-C analysis. In addition, enrichment in the repressive mark H3K27me3 invades the Car5b domain in deleted cells, consistent with loss of expression from the Xi. In contrast, cells with an inversion of the CTCF binding site retain CTCF and cohesin binding, as well as looping, in line with persistence of escape. Interestingly, the levels of escape increase in cells with deletion of either Dxz4, which disrupts the Xi-specific compact 3D structure, or Firre, which results in lower H3K27me3 enrichment on the Xi, indicating that the structural and epigenetic features of the Xi constrain escape from XCI in wild type conditions.ConclusionsTaken together, our findings support the idea that escape from XCI in female somatic cells is modulated by both the topological insulation of domains via CTCF binding and the surrounding heterochromatin environment.
| S-EPMC11874400 | biostudies-literature
Project description:BackgroundThe number and escape levels of genes that escape X chromosome inactivation (XCI) in female somatic cells vary among tissues and cell types, potentially contributing to specific sex differences. Here we investigate the role of CTCF, a master chromatin conformation regulator, in regulating escape from XCI. CTCF binding profiles and epigenetic features were systematically examined at constitutive and facultative escape genes using mouse allelic systems to distinguish the inactive X (Xi) and active X (Xa) chromosomes.ResultsWe found that escape genes are located inside domains flanked by convergent arrays of CTCF binding sites, consistent with the formation of loops. In addition, strong and divergent CTCF binding sites often located at the boundaries between escape genes and adjacent neighbors subject to XCI would help insulate domains. Facultative escapees show clear differences in CTCF binding dependent on their XCI status in specific cell types/tissues. Concordantly, deletion but not inversion of a CTCF binding site at the boundary between the facultative escape gene Car5b and its silent neighbor Siah1b resulted in loss of Car5b escape. Reduced CTCF binding and enrichment of a repressive mark over Car5b in cells with a boundary deletion indicated loss of looping and insulation. In mutant lines in which either the Xi-specific compact structure or its H3K27me3 enrichment was disrupted, escape genes showed an increase in gene expression and associated active marks, supporting the roles of the 3D Xi structure and heterochromatic marks in constraining levels of escape.ConclusionOur findings indicate that escape from XCI is modulated both by looping and insulation of chromatin via convergent arrays of CTCF binding sites and by compaction and epigenetic features of the surrounding heterochromatin.
| S-EPMC10187265 | biostudies-literature
Project description:Genes that escape X chromosome inactivation modulate sex differences in valve myofibroblasts
| PRJNA731684 | ENA
Project description:X chromosome inactivation (XCI) silences most genes on one X chromosome in female mammals, but some genes escape XCI. To identify escape gene in vivo and to explore molecular mechanisms that regulate this process we analyzed the allele-specific expression and chromatin structure of X-linked genes in mouse tissues and cells with skewed XCI and distinguishable alleles based on single nucleotide polymorphisms. Using a new method to estimate allelic expression, we demonstrate a continuum between complete silencing and significant expression from the inactive X (Xi). Few genes (2-3%) escape XCI to a significant level and only a minority differs between mouse tissues, suggesting stringent silencing and escape controls. Allelic profiles of DNase I hypersensitivity and RNA polymerase II occupancy of genes on the Xi correlate with escape from XCI. Allelic binding profiles of the DNA binding protein CCCTC-binding factor (CTCF) in different cell types indicate that CTCF binding at the promoter correlates with escape. Importantly, CTCF binding at the boundary between escape and silenced domains may prevent the spreading of active escape chromatin into silenced domains.
2015-02-20 | GSE59777 | GEO