The inactive X chromosome adopts a unique three-dimensional conformation that is dependent on Xist RNA.
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE29509 | GEO | 2011/06/24
SECONDARY ACCESSION(S): PRJNA141457
REPOSITORIES: GEO
Similar Datasets
Project description:3D-topology of DNA in the cell nucleus provides a level of transcription regulation beyond the sequence of the linear DNA. To study the relationship between transcriptional activity and spatial environment of a gene, we have used allele-specific 4C-technology to produce high-resolution topology maps of the active and inactive X-chromosomes in female cells. We found that loci on the active X form multiple long-range interactions, with spatial segregation of active and inactive chromatin. On the inactive X, silenced loci lack preferred interactions, suggesting a unique random organization inside the inactive territory. However, escapees, among which is Xist, are engaged in long-range contacts with each other, enabling identification of novel escapees. Deletion of Xist results in partial re-folding of the inactive X into a conformation resembling the active X, without affecting gene silencing or DNA methylation. Our data point to a role for Xist RNA in shaping the conformation of the inactive X-chromosome independently of transcription. Five or six 4C viewpoints were applied on the mouse female wild type active X-chromosome, the wild type inactive X-chromosome, the conditional Xist X-chromosome and the Xist knock out X-chromosome
2011-06-24 | E-GEOD-29509 | biostudies-arrayexpress
Project description:The spatial organization of DNA in the cell nucleus is an emerging key contributor to genomic function. We have developed 4C technology, or 3C-on-chip, which allows for an unbiased genome-wide search for DNA loci that contact a given locus in the nuclear space. We demonstrate here that active and inactive genes are engaged in many long-range intrachromosomal interactions and can also form interchromosomal contacts. The active b-globin locus in fetal liver contacts mostly transcribed, but not necessarily tissue-specific, loci elsewhere on chromosome 7, while the inactive locus in fetal brain contacts different, transcriptionally silent, loci. A housekeeping gene in a gene dense region on chromosome 8 forms long-range contacts predominantly with other active gene clusters, both in cis and in trans, and many of these intra- and interchromosomal interactions are conserved between the tissues analyzed. Our data demonstrate that chromosomes fold into areas of active chromatin and areas of inactive chromatin and establish 4C technology as a powerful tool to study nuclear architecture. Keywords: 4C technology
2006-09-22 | GSE5891 | GEO
Project description:X-chromosome inactivation (XCI) provides a dosage compensation mechanism where, in each female cell, one of the two X chromosomes is randomly silenced. However, some genes on the inactive X chromosome and outside the pseudoautosomal regions escape from XCI and are expressed from both alleles (escapees). We investigated XCI at single-cell resolution combining deep single cellRNA sequencing with whole-genome sequencing to examine allelic-specific expression in 935 primary fibroblast and 48 lymphoblastoid single cells from five female individuals. In this framework we integrated an original method to identify and exclude doublets of cells. In fibroblast cells, we have identified 55 genes as escapees including five novel escapee genes. Moreover, we observed that all genes exhibit a variable propensity to escape XCI in each cell and cell type and that each cell displays a distinct expression profile of the escapee genes. A metric, the Inactivation Score—defined as the mean of the allelic expression profiles of the escapees per cell—enables us to discover a heterogeneous and continuous degree of cellular XCI with extremes represented by “inactive” cells, i.e., cells exclusively expressing the escaping genes from the active X chromosome and “escaping” cells expressing the escapees from both alleles. We found that this effect is associated with cell-cycle phases and, independently, with the XIST expression level, which is higher in the quiescent phase (G0). Single-cell allele-specific expression is a powerful tool to identify novel escapees in different tissues and provide evidence of an unexpected cellular heterogeneity of XCI.
2019-01-02 | GSE123028 | GEO
Project description:The inactive X chromosome (Xi) serves as a model to understand gene silencing on a global scale. Here, we perform identification of direct RNA interacting proteins? (iDRiP) to isolate a comprehensive protein interactome for Xist, an RNA required for Xi silencing. We discover multiple classes of interactors, including cohesins, condensins, topoisomerases, RNA helicases, chromatin remodelers and modifiers, which synergistically repress Xi transcription. Inhibiting two or three interactors destabilizes silencing. While Xist attracts some interactors, it repels architectural factors. Xist evicts cohesins from the Xi and directs an Xi-specific chromosome conformation. Upon deleting Xist, the Xi acquires the cohesin-binding and chromosomal architecture of the active X. Our study unveils many layers of Xi repression and demonstrates a central role for RNA in the topological organization of mammalian chromosomes. The RNA-seq data sets generated in this study provide a resource for examining the effects of knockdowns of various Xist-interacting proteins on gene expression. The ChIP-seq data sets provide a comprehensive set of data examining CTCF and cohesion binding the X-chromosome, and the effects of deleting Xist on CTCF and cohesion binding. The Hi-C data is an allele-specific contact map of the X-chromosome higher-order chromatin structure in mouse. RNA-seq in 3 control and 10 knockdown cell lines. ChIP-seq for CTCF, Rad21 and Smc1a in wild-type fibroblasts and Xist-deletion fibroblasts. Hi-C in wild-type and Xist-deletion fibroblasts.
2015-06-19 | E-GEOD-67516 | biostudies-arrayexpress
Project description:One of the two X chromosomes in female somatic cells is transcriptionally silenced across cell generations, a classic paradigm of epigenetic regulation. Although most genes are stably silenced, certain X-linked genes escape X-chromosome inactivation (XCI), providing a fundamental dosage difference between females and males. A role for chromosome conformation has been proposed in XCI as the process is accompanied by a massive structural reorganisation. However a detailed molecular understanding of the three-dimensional architecture of the Xi has been lacking. Here we reveal an unusual three-dimensional configuration of the Xi, that provides novel insights into the relationship between gene expression and TAD organisation. Using allele-specific Hi-C, RNA-Seq and ATAC-seq, as well as DNA FISH, we show that the Xi is spatially segregated into two ‘mega-domains’ separated by a 200kb boundary including the DXZ4 macrosatellite, and is globally devoid of typical autosomal structural features such as active/inactive compartments and topologically associating domains (TADs). However, we find that a few regions along the Xi display TAD signatures corresponding to regions containing escape genes, and display DNA accessibility at promoter-proximal TF binding sites. Strikingly, when the DXZ4-containing boundary region is deleted prior to XCI, most facultative escapees are no longer expressed from the Xi, and the escape associated chromatin domains are no longer observed. Deletion of the DXZ4-containing boundary region from the Xi also results in fusion of the two mega-domains. We show that Xist A-repeat containing (gene silencing competent) RNA is sufficient to induce this spatial segregation of the X chromosome. Combined, our results point to a critical role for the DXZ4-boundary region, together with Xist RNA, in shaping the higher order structure of the Xi and in allowing facultative escape from XCI during differentiation. They also point to direct and uncover a close relationships between transcription and TAD formation organisation in the context of the Xi.
2016-06-30 | GSE71156 | GEO
Project description:The spatial and temporal control of Hox gene transcription is essential for patterning the vertebrate body axis. Although this process involves changes in histone posttranslational modifications, the existence of particular three-dimensional (3D) architectures remained to be assessed in vivo. Using high-resolution chromatin conformation capture methodology, we examined the spatial configuration of Hox clusters in embryonic mouse tissues where different Hox genes are active. When the cluster is transcriptionally inactive, Hox genes associate into a single 3D structure delimited from flanking regions. Once transcription starts, Hox clusters switch to a bimodal 3D organization where newly activated genes progressively cluster into a transcriptionally active compartment. This transition in spatial configurations coincides with the dynamics of chromatin marks, which label the progression of the gene clusters from a negative to a positive transcription status. This spatial compartmentalization may be key to process the collinear activation of these compact gene clusters. Examination of gene expression in 3 cell types. Examination of 2 different histone modifications in 2 cell types.
2011-10-12 | E-GEOD-31570 | biostudies-arrayexpress
Project description:Whereas spatial genome organization at large scale of compartments and topologically associating domains (TADs) is relatively well studied, the spatial organization of regulatory elements at finer scales is poorly understood in plants. Here, using high-resolution chromatin interaction analysis by paired-end tag sequencing (ChIA-PET) approach, we mapped histone modification-marked DNA elements-associated and RNA polymerase II (RNAPII)-tethered chromatin interactions involving in transcriptionally active, inactive and Polycomb-repressed states in Arabidopsis. Analysis of the regulatory repertoire showed that both active proximal and distal cis-regulatory elements (CREs) promote the transcription of their nearest and long-range connecting genes; poised CREs act as transcriptional repressors to repress their interacting genes’ expression, indicating that the linear juxtaposition is not the only guiding principle modulating gene transcription. Chromatin connectivity networks revealed that genes implicating in flowering-time control are functionally compartmentalized into separate subnuclear domains, linking active mark- and H3K27me3-associated chromatin conformation to coordinated gene expression. Our study uncovers fine-scale Arabidopsis genome organization and their roles in orchestrating transcription and development.
2023-07-10 | GSE207010 | GEO
Project description:JARID2 ChIP-seq profile mediated by Xist was investigated using two separate approaches: In the first approach, we use the TX1072 female embryonic stem cell (ESC) line; this is a genetically polymorphic ESC line derived from a mouse with one X-chromosome (X-chr) from the Mus musculus castaneus (Cast) origin and the other of Mus musculus domesticus, C57BL/6 (BL6) strain origin, containing an inducible promoter on the BL6 Xist allele; differentiation and simultaneous induction of Xist for 4 days results in the inactivation of ONLY the BL6-derived X-chr and coating by JARID2 protein. We analysed this ESC line in the undifferentiated state, in which both X-chrs are active (and not coated by JARID2), and also after 4 days of differentiation under Xist inducible conditions, in which cells display one inactive X-chr from BL6 origin and one Xa of the Cast origin; the presence of SNPs allows for the comparison of the degree and localisation of JARID2 enrichment on the inactive X-chr versus the active X-chr; our results suggests that JARID2 is enriched on the inactive X-chr chromosome-wide and not in confined peaks as elsewhere in the genome; This pattern resembles patterns of Xist enrichment published before (Engreitz et al., 2013). In the second approach, we use a male ESC line that carries an inducible Xist transgene (TG) on chromosome 11 (chr11) (Wutz et al., 2000) in the presence (36:11 WT) or the absence of Eed (36:11 Eed-/-) Induction of Xist TG results in Xist coating and enrichment of JARID2 across the chr11, regardless of the presence of Eed when assess by IF/Xist RNA FISH experiments. We compare inducible and uninducible condition in both the 36:11 WT and Eed-/- ESCs; this way, we could assess the Xist-mediated JARID2 recruitment and the effect of the absence of Eed-/-; Our results shows that Xist induction result in a chromosome-wide enrichment of JARID2 on chr11, in a manner that resembles enrichment on the inactive X-chr; this pattern seem to be independent of EED, showing that in contrast to other regions in the genome where JARID2 occupancy is abrogated in the absence of EED, Xist-mediated JARID2 recruitment is not affected. JARID2 ChIP-seq analysis in differentiating female ESCs (TX1072) and in a male ESC harbouring a Xist transgene on chromosome 11 in WT and Eed-/- genetics settings
2014-01-23 | E-GEOD-52073 | biostudies-arrayexpress
Project description:X-chromosome inactivation (XCI) entails a massive structural reorganization of the inactive X (Xi). However the molecular architecture of the Xi is unknown. Here we show that the Xi lacks typical autosomal features such as active/inactive compartments and topologically associating domains (TADs), except around a small number of genes that escape XCI and remain expressed. Escaping genes form TADs and retain DNA accessibility at promoter-proximal and CTCF binding sites, indicating that these loci can avoid Xist-mediated erasure of chromosomal structure. We further show that genesilencing competent Xist RNA is sufficient to induce segregation of the Xi into two ‘mega-domains’ separated by a boundary that includes the DXZ4 macrosatellite. Deletion of this boundary prior to XCI results in fusion of the megadomains and altered patterns of escape that correlate with changes in TAD structure following differentiation and XCI . Our results suggest a critical role for the boundary locus and Xist RNA in shaping the structure of the Xi and modulating escape from XCI. Our findings also point to roles of transcription and CTCF binding in TAD formation in the context of facultative heterochromatin.
2016-07-18 | GSE72697 | GEO
Project description:Chromosome conformation capture technologies have revealed important insights into genome folding. Yet, how spatial genome architecture is related to gene expression and cell fate remains unclear. We mapped comprehensively 3D chromatin organization during mouse neural differentiation in vitro and in vivo, generating the highest resolution Hi-C maps available to date. We found that transcription is correlated with chromatin insulation and long-range interactions, but dCas9-mediated activation is insufficient for creating topological domain (TAD) boundaries de novo. Additionally, we discovered long-range contacts between gene bodies of exon-rich, active genes in all cell types. During neural differentiation, contacts between active TADs become less pronounced while inactive TADs interact stronger. An extensive Polycomb network in stem cells is disrupted, while dynamic interactions between proneural transcription factors appear in vivo. Finally, cell-type specific enhancer-promoter contacts are established concomitant to gene expression. This work shows that multiple factors influence the dynamics of chromatin interactions in development.
2017-10-18 | GSE96107 | GEO