Perturbed maintenance of transcriptional repression on the inactive X-chromosome in the mouse brain after XIST deletion
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE119066 | GEO | 2018/08/28
REPOSITORIES: GEO
Similar Datasets
Project description:In mammals, genes located on the X chromosome are present in one copy in XY males and two in XX females. To balance the dosage of X-linked gene expression between the sexes one of the two X chromosomes in females is silenced by X inactivation initiated by up-regulation of the lncRNA (long non-coding RNA) Xist and recruitment of specific chromatin modifiers for silencing. The inactivated X chromosome becomes heterochromatic and visits a specific nuclear compartment adjacent to the nucleolus. We report a novel role for the X-linked lncRNA Firre in anchoring the inactive mouse X chromosome and preserving one of its main epigenetic features, trimethylation of histone H3 at lysine 27 (H3K27me3). Similar to Dxz4, Firre is expressed from a macrosatellite repeat locus associated with a cluster of CTCF and cohesin binding specifically on the inactive X. CTCF binding initially present in both male and female mouse embryonic stem cells was found to be lost from the active X during development. The Firre and Dxz4 loci on the inactive X were preferentially located adjacent to the nucleolus. Knockdown of Firre RNA disrupted perinucleolar targeting and H3K27me3 levels in mouse fibroblasts, demonstrating an important role for this lncRNA in maintenance of one of the main epigenetic features of the X chromosome. There was no X-linked gene reactivation after Firre knockdown; however, a compensatory increase in the expression of chromatin modifier genes implicated in X silencing was observed. In female ES cells Firre RNA knockdown did not disrupt Xist expression/coating nor silencing of G6pdx during differentiation, suggesting that Firre does not play a role in the onset of X inactivation. We conclude that the X-linked lncRNA Firre helps position the inactive X chromosome near the nucleolus and preserve one of its main epigenetic features. Examination of allelic expression in Patski cells upon Firre knockdown.
2015-03-05 | E-GEOD-66172 | biostudies-arrayexpress
Project description:In mammals, genes located on the X chromosome are present in one copy in XY males and two in XX females. To balance the dosage of X-linked gene expression between the sexes one of the two X chromosomes in females is silenced by X inactivation initiated by up-regulation of the lncRNA (long non-coding RNA) Xist and recruitment of specific chromatin modifiers for silencing. The inactivated X chromosome becomes heterochromatic and visits a specific nuclear compartment adjacent to the nucleolus. We report a novel role for the X-linked lncRNA Firre in anchoring the inactive mouse X chromosome and preserving one of its main epigenetic features, trimethylation of histone H3 at lysine 27 (H3K27me3). Similar to Dxz4, Firre is expressed from a macrosatellite repeat locus associated with a cluster of CTCF and cohesin binding specifically on the inactive X. CTCF binding initially present in both male and female mouse embryonic stem cells was found to be lost from the active X during development. The Firre and Dxz4 loci on the inactive X were preferentially located adjacent to the nucleolus. Knockdown of Firre RNA disrupted perinucleolar targeting and H3K27me3 levels in mouse fibroblasts, demonstrating an important role for this lncRNA in maintenance of one of the main epigenetic features of the X chromosome. There was no X-linked gene reactivation after Firre knockdown; however, a compensatory increase in the expression of chromatin modifier genes implicated in X silencing was observed. In female ES cells Firre RNA knockdown did not disrupt Xist expression/coating nor silencing of G6pdx during differentiation, suggesting that Firre does not play a role in the onset of X inactivation. We conclude that the X-linked lncRNA Firre helps position the inactive X chromosome near the nucleolus and preserve one of its main epigenetic features. Examination of allelic protein-binding or histone modification profiles in Patski cells.
2015-02-26 | E-GEOD-66262 | biostudies-arrayexpress
Project description:At initiation of X chromosome inactivation (XCI), Xist is monoallelically upregulated from the future inactive X (Xi) chromosome, overcoming repression by its antisense transcript Tsix. Xist recruits various chromatin remodelers, amongst them SPEN, which are involved in silencing of X-linked genes in cis and establishment of the Xi. Here, we show that SPEN plays an important role in the initiation of XCI. Spen null female mouse embryonic stem cells (ESCs) are defective in Xist upregulation upon differentiation. We find that Xist-mediated SPEN recruitment to the Xi chromosome happens very early in XCI, and that SPEN-mediated silencing of the Tsix promoter is required for Xist upregulation. Accordingly, failed Xist upregulation in Spen-/- ESCs can be rescued by concomitant removal of Tsix. These findings indicate that SPEN is not only required for the establishment of the Xi, but is also crucial in the initiation of the XCI process.
2021-09-30 | GSE163320 | GEO
Project description:At initiation of X chromosome inactivation (XCI), Xist is monoallelically upregulated from the future inactive X (Xi) chromosome, overcoming repression by its antisense transcript Tsix. Xist recruits various chromatin remodelers, amongst them SPEN, which are involved in silencing of X-linked genes in cis and establishment of the Xi. Here, we show that SPEN plays an important role in the initiation of XCI. Spen null female mouse embryonic stem cells (ESCs) are defective in Xist upregulation upon differentiation. We find that Xist-mediated SPEN recruitment to the Xi chromosome happens very early in XCI, and that SPEN-mediated silencing of the Tsix promoter is required for Xist upregulation. Accordingly, failed Xist upregulation in Spen-/- ESCs can be rescued by concomitant removal of Tsix. These findings indicate that SPEN is not only required for the establishment of the Xi, but is also crucial in the initiation of the XCI process.
2021-09-30 | GSE163319 | GEO
Project description:X chromosome inactivation (XCI) in female lymphocytes is uniquely regulated, as the inactive X (Xi) chromosome lacks localized Xist RNA and heterochromatin modifications. Epigenetic profiling reveals that Xist RNA is lost from the Xi at the pro-B cell stage and that additional heterochromatic modifications are gradually lost during B cell development. Activation of mature B cells restores Xist RNA and heterochromatin to the Xi in a dynamic two-step process that differs in timing and pattern, depending on the method of B cell stimulation. Finally, we find that DNA binding by YY1 maintains XCI in activated B cells, as ex-vivo YY1 deletion results in loss of Xi heterochromatin marks and up-regulation of X-linked genes. Ectopic expression of the YY1 zinc finger domain is sufficient for Xist RNA localization during B cell activation. Together, our results indicate that Xist RNA localization is critical for maintaining XCI in female lymphocytes, and that chromatin changes on the Xi during B cell development and the dynamic nature of YY1-dependent XCI maintenance in mature B cells predisposes X- linked immunity genes to reactivation.
2018-02-22 | GSE104097 | GEO
Project description:Naïve human embryonic stem cells (hESCs) can be derived from primed hESCs or directly from blastocysts, but their X-chromosome state has remained unresolved. We found that the inactive X-chromosome (Xi) of primed hESCs was reactivated in naïve culture conditions. Similar to cells of the blastocyst, resulting naive cells exhibited two active X-chromosomes with XIST expression and chromosome-wide transcriptional dampening, and initiated XIST-mediated X-inactivation upon differentiation. Both establishment and exit from the naïve state (differentiation) happened via an XIST-negative XaXa intermediate. Together, these findings identify a cell culture system for functionally exploring the two X-chromosome dosage compensation processes in early human development: X-dampening and X-inactivation. Furthermore, the naïve state reset Xi abnormalities of primed hESCs, providing cells better suited for downstream applications. However, naïve hESCs displayed differences to the embryo because XIST expression was predominantly mono-allelic instead of bi-allelic, and X-inactivation was non-random, indicating the need for further culture improvement.
2016-10-21 | GSE87235 | GEO
Project description:Naïve human embryonic stem cells (hESCs) can be derived from primed hESCs or directly from blastocysts, but their X-chromosome state has remained unresolved. We found that the inactive X-chromosome (Xi) of primed hESCs was reactivated in naïve culture conditions. Similar to cells of the blastocyst, resulting naive cells exhibited two active X-chromosomes with XIST expression and chromosome-wide transcriptional dampening, and initiated XIST-mediated X-inactivation upon differentiation. Both establishment and exit from the naïve state (differentiation) happened via an XIST-negative XaXa intermediate. Together, these findings identify a cell culture system for functionally exploring the two X-chromosome dosage compensation processes in early human development: X-dampening and X-inactivation. Furthermore, the naïve state reset Xi abnormalities of primed hESCs, providing cells better suited for downstream applications. However, naïve hESCs displayed differences to the embryo because XIST expression was predominantly mono-allelic instead of bi-allelic, and X-inactivation was non-random, indicating the need for further culture improvement.
2016-10-21 | GSE87231 | GEO
Project description:Naïve human embryonic stem cells (hESCs) can be derived from primed hESCs or directly from blastocysts, but their X-chromosome state has remained unresolved. We found that the inactive X-chromosome (Xi) of primed hESCs was reactivated in naïve culture conditions. Similar to cells of the blastocyst, resulting naive cells exhibited two active X-chromosomes with XIST expression and chromosome-wide transcriptional dampening, and initiated XIST-mediated X-inactivation upon differentiation. Both establishment and exit from the naïve state (differentiation) happened via an XIST-negative XaXa intermediate. Together, these findings identify a cell culture system for functionally exploring the two X-chromosome dosage compensation processes in early human development: X-dampening and X-inactivation. Furthermore, the naïve state reset Xi abnormalities of primed hESCs, providing cells better suited for downstream applications. However, naïve hESCs displayed differences to the embryo because XIST expression was predominantly mono-allelic instead of bi-allelic, and X-inactivation was non-random, indicating the need for further culture improvement.
2016-10-21 | GSE87237 | GEO
Project description:The Xist long noncoding RNA (lncRNA) is essential for X-chromosome inactivation (XCI), the process by which mammals compensate for unequal numbers of sex chromosomes. During XCI, Xist coats the future inactive X (Xi) and recruits Polycomb Repressive Complex 2 (PRC2) to the X-inactivation center (Xic). Currently unclear is how Xist spreads silencing on a 150 Mb scale. Here we generate high-resolution maps of Xist binding across a developmental time course using CHART-seq. In female cells undergoing XCI de novo, Xist follows a two-step mechanism in which it initially targets gene-rich islands before spreading to intervening gene-poor domains. Xist is depleted from genes that escape XCI but frequently concentrates near escapee boundaries. Xist binding was linearly proportional to PRC2 density and H3 lysine 27 trimethylation (H3K27me3), suggesting co-migration of Xist and PRC2. Interestingly, when the Xi is acutely stripped of Xist in post-XCI cells, Xist recovers quickly within both gene-rich and -poor domains on a time scale of hours instead of days, suggesting a previously primed Xi chromatin state. We conclude that Xist spreading takes on distinct stage-specific forms: During initial establishment, Xist follows a two-step mechanism, but during maintenance, Xist spreads rapidly to both gene-rich and -poor regions. Capture hybridization analysis of RNA targets (CHART) and input samples of (differentiating) mouse embryonic stem (ES) cells and immortalized mouse embryonic fibroblasts (MEF) using paired-end 75 nt reads on Illumina HiSeq2500, with 2 replicates per sample (# of samples). RNA-seq of the same cell lines with 50 nt reads on Illumina HiSeq2000, with 2 replicates per sample (2 samples, 4 datasets total). CHIP-seq: Data from GSE36905 was aligned and processed as CHART-seq samples. Resulting coverage tracks (EZH2/K27me3) are linked directly to GSE48649 (bedGraphs linked below).
2013-11-04 | E-GEOD-48649 | biostudies-arrayexpress
Project description:The Xist long noncoding RNA (lncRNA) is essential for X-chromosome inactivation (XCI), the process by which mammals compensate for unequal numbers of sex chromosomes. During XCI, Xist coats the future inactive X (Xi) and recruits Polycomb Repressive Complex 2 (PRC2) to the X-inactivation center (Xic). Currently unclear is how Xist spreads silencing on a 150 Mb scale. Here we generate high-resolution maps of Xist binding across a developmental time course using CHART-seq. In female cells undergoing XCI de novo, Xist follows a two-step mechanism in which it initially targets gene-rich islands before spreading to intervening gene-poor domains. Xist is depleted from genes that escape XCI but frequently concentrates near escapee boundaries. Xist binding was linearly proportional to PRC2 density and H3 lysine 27 trimethylation (H3K27me3), suggesting co-migration of Xist and PRC2. Interestingly, when the Xi is acutely stripped of Xist in post-XCI cells, Xist recovers quickly within both gene-rich and -poor domains on a time scale of hours instead of days, suggesting a previously primed Xi chromatin state. We conclude that Xist spreading takes on distinct stage-specific forms: During initial establishment, Xist follows a two-step mechanism, but during maintenance, Xist spreads rapidly to both gene-rich and -poor regions.
2013-11-04 | GSE48649 | GEO