Defects in dosage compensation impact global gene regulation in the mouse trophoblast
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE93031 | GEO | 2017/07/17
SECONDARY ACCESSION(S): PRJNA359489
REPOSITORIES: GEO
Similar Datasets
Project description:X chromosome inactivation (XCI) compensates for differences in X-chromosome number between male and female mammals. XCI is orchestrated by Xist RNA, whose expression in early development leads to transcriptional silencing of one X-chromosome in the female. Knockout studies have established a requirement for Xist, with inviability of female embryos that inherit an Xist deletion from the father. Here, we report that female mice lacking Xist RNA can, surprisingly, develop and survive to term. Xist-null females are born at lower frequency and are smaller at birth, but organogenesis is mostly normal. Transcriptomic analysis indicates significant overexpression of hundreds of X-linked genes across multiple tissues. Therefore, Xist-null mice can develop to term in spite of a deficiency of dosage compensation. However, the degree of X-autosomal dosage imbalance was less than anticipated (1.14- to 1.36-fold). Thus, partial dosage compensation can be achieved without Xist, supporting the idea of inherent genome balance. Nevertheless, to date, none of the mutant mice has survived beyond weaning stage. Sudden death is associated with failure of postnatal organ maturation. Our data suggest Xist-independent mechanisms of dosage compensation and demonstrate that small deviations from X-autosomal balance can have profound effects on overall fitness. RNA-sequencing of tail-tip fibroblasts (TTFs), spleen, liver and heart tissue from Xist-null and control female mice. Sequencing performed with 50nt read length on Illumina HiSeq2000 or 2500. Data consists of 3 biological replicates for TTFs (6 datasets) and 2 biological replicates for tissues (12 datasets).
2016-08-19 | E-GEOD-84665 | biostudies-arrayexpress
Project description:X chromosome inactivation (XCI) compensates for differences in X-chromosome number between male and female mammals. XCI is orchestrated by Xist RNA, whose expression in early development leads to transcriptional silencing of one X-chromosome in the female. Knockout studies have established a requirement for Xist, with inviability of female embryos that inherit an Xist deletion from the father. Here, we report that female mice lacking Xist RNA can, surprisingly, develop and survive to term. Xist-null females are born at lower frequency and are smaller at birth, but organogenesis is mostly normal. Transcriptomic analysis indicates significant overexpression of hundreds of X-linked genes across multiple tissues. Therefore, Xist-null mice can develop to term in spite of a deficiency of dosage compensation. However, the degree of X-autosomal dosage imbalance was less than anticipated (1.14- to 1.36-fold). Thus, partial dosage compensation can be achieved without Xist, supporting the idea of inherent genome balance. Nevertheless, to date, none of the mutant mice has survived beyond weaning stage. Sudden death is associated with failure of postnatal organ maturation. Our data suggest Xist-independent mechanisms of dosage compensation and demonstrate that small deviations from X-autosomal balance can have profound effects on overall fitness.
2016-08-19 | GSE84665 | GEO
Project description:Down syndrome is a common disorder with enormous medical and social costs, caused by trisomy for Chr21. We tested the concept that gene imbalance across an extra chromosome can be de facto corrected in DS patient stem cells by manipulating a single gene, XIST. Using zinc finger nucleases, we targeted a large, inducible XIST transgene into the Chr21 DYRK1A locus, in DS pluripotent stem cells. XIST RNA coats Chr21 and triggers stable heterochromatin modifications, chromosome-wide transcriptional silencing and DNA methylation to form a “Chr21 Barr Body.” This provides a model to study human chromosome inactivation and creates a system to investigate genomic expression changes and cellular pathologies of trisomy 21, free from genetic and epigenetic noise. In this study, we used microarrays to understand the genome-wide impacts of inducible XIST expression on Chr21 in trisomy 21 human iPS cell lines, and to evaluate the extent of Chr21 silencing trisomic samples versus a disomic male iPS cell line.
2013-07-12 | GSE47014 | GEO
Project description:Down syndrome is a common disorder with enormous medical and social costs, caused by trisomy for Chr21. We tested the concept that gene imbalance across an extra chromosome can be de facto corrected in DS patient stem cells by manipulating a single gene, XIST. Using zinc finger nucleases, we targeted a large, inducible XIST transgene into the Chr21 DYRK1A locus, in DS pluripotent stem cells. XIST RNA coats Chr21 and triggers stable heterochromatin modifications, chromosome-wide transcriptional silencing and DNA methylation to form a M-bM-^@M-^\Chr21 Barr Body.M-bM-^@M-^] This provides a model to study human chromosome inactivation and creates a system to investigate genomic expression changes and cellular pathologies of trisomy 21, free from genetic and epigenetic noise. In this study, we used microarrays to understand the genome-wide impacts of inducible XIST expression on Chr21 in trisomy 21 human iPS cell lines, and to evaluate the extent of Chr21 silencing trisomic samples versus a disomic male iPS cell line. Three independently targeted subclones plus the parental Chr21 trisomic (non-targeted) iPS cell line were grown M-BM-1 doxycycline (2 M-BM-5g/ml) for 22 d. Normal male iPS line was also cultured for 22 d and total RNA was extracted with a High Pure RNA extraction kit (Roche) in triplicate for each, processed with a Gene Chip 3M-bM-^@M-^Y IVT Express Kit (Affymetrix), and hybridized to Affymetrix human gene expression PrimeView arrays. Array normalization was performed with Affymetrix Expression Console Software with Robust Multichip Analysis (RMA). Probesets with the top 60% of signal values were considered present and M-bM-^@M-^\expressedM-bM-^@M-^] and were used for all further analysis. In total 9 RNA samples were prepared in triplicate for a total of 27 arrays.
2013-07-12 | E-GEOD-47014 | biostudies-arrayexpress
Project description:Cloning mammals by somatic cell nuclear transfer (SCNT) is highly inefficient. Most SCNT-generated embryos die after implantation because of unidentified, complex epigenetic errors in the process of postimplantation embryonic development. Here, we identified the most upstream level of dysfunction leading to impaired development of clones by using RNA interference (RNAi) against Xist, a gene responsible for X chromosome inactivation (XCI). A prior injection of Xist-specific short interfering (si)RNA into reconstructed oocytes efficiently corrected the SCNT-specific aberrant Xist expression at the morula stage, but failed to do so thereafter at the blastocyst stage. However, we found that shortly after implantation this aberrant XCI status in cloned embryos had been corrected autonomously in both embryonic and extraembryonic tissues, probably through a newly established XCI control for postimplantation embryos. Embryo transfer experiments revealed that the siRNA-treated embryos showed 10 times higher survival than controls as early as embryonic day 5.5 and this high survival persisted until term, resulting in a remarkable improvement in cloning efficiency (12% vs. 1% in controls). Importantly, unlike control clones, these Xist-siRNA clones at birth showed only a limited dysregulation of their gene expression, indicating that correction of Xist expression in preimplantation embryos had a long-term effect on their postnatal normality. Thus, contrary to the general assumption, our results suggest that the fate of cloned embryos is determined almost exclusively before implantation by their XCI status. Furthermore, our strategy provides a promising breakthrough for mammalian SCNT cloning because RNAi treatment of oocytes is readily applicable to most mammal species. Gene expression were measured in mouse in vitro fertilized and somatic cell cloned embryos. Four biological replicates were performed in each group of Xist- or Control-siRNA.
2011-11-17 | E-GEOD-33208 | biostudies-arrayexpress
Project description:Xist represents a paradigm for long non-coding RNA function in epigenetic regulation, although how it mediates X-chromosome inactivation (XCI) remains largely unexplained. Multiple Xist-RNA binding proteins have recently been identified, including SPEN/SHARP, whose knockdown has been associated with deficient XCI at multiple loci. Here we demonstrate that SPEN is a key orchestrator of XCI in vivo and unravel its mechanism of action. We show that SPEN is essential for initiating gene silencing on the X chromosome in preimplantation mouse embryos and embryonic stem cells. On the other hand, SPEN is dispensable for maintenance of XCI in neural progenitor cells, although it significantly dampens expression of genes that escape from XCI. During initiation of XCI, we show by live-cell imaging and CUT&RUN approaches that SPEN is immediately recruited to the X chromosome upon Xist up-regulation, where it is targeted to enhancers and promoters of actively transcribed genes. SPEN rapidly disengages from chromatin once silencing is accomplished, implying a need for active transcription to tether it to chromatin. We define SPEN’s SPOC (SPEN paralog and ortholog C-terminal) domain as a major effector of SPEN’s gene silencing function, and show that artificial tethering of SPOC to Xist RNA is sufficient to mediate X-linked gene silencing. We identify SPOC’s protein partners which include NCOR/SMRT, the m6A RNA methylation machinery, the NuRD complex, RNA polymerase II and factors involved in regulation of transcription initiation and elongation. We propose that SPEN acts as a molecular integrator for initiation of XCI, bridging Xist RNA with the transcription machinery as well as nucleosome remodelers and histone deacetylases, at active enhancers and promoters.
2021-04-19 | PXD015699 | Pride
Project description:Developmental genes such as Xist, the master regulator of X-chromosome inactivation (XCI), are controlled by complex cis-regulatory landscapes, which decode multiple signals to establish specific spatio-temporal expression patterns. Xist integrates information on X-chromosomal dosage and developmental stage to trigger XCI at the primed pluripotent state in females only. Through a pooled CRISPR interference screen in differentiating mouse embryonic stem cells, we identify functional enhancer elements of Xist during the onset of random XCI. By quantifying how enhancer activity is modulated by X-dosage and differentiation, we find that X-dosage controls the promoter-proximal region in a binary switch-like manner. By contrast, differentiation cues activate a series of distal elements and bring them into closer spatial proximity of the Xist promoter. The strongest distal element is part of an enhancer cluster ~200 kb upstream of the Xist gene which is associated with a previously unannotated Xist-enhancing regulatory transcript, we named Xert. Developmental cues and X-dosage are thus decoded by distinct regulatory regions, which cooperate to ensure female-specific Xist upregulation at the correct developmental time. Our study is the first step to disentangle how multiple, functionally distinct regulatory regions interact to generate complex expression patterns in mammals.
2021-03-04 | GSE167358 | GEO
Project description:X-chromosome dosage compensation ensures balanced gene dosage between the X chromosome and autosomes and between the sexes, involving divergent mechanisms among mammals. We elucidated a distinct mechanism for X-chromosome inactivation (XCI) in cynomolgus monkeys, a model for human development. The trophectoderm and cytotrophoblast acquire XCI around implantation through an active intermediate bearing repressive modifications and compacted structure, whereas the amnion, epiblast, and hypoblast maintain such an intermediate protractedly, attaining XCI by a week after implantation. Males achieve X-chromosome up-regulation (XCU) progressively, whereas females show XCU coincidentally with XCI, both establishing the X:autosome dosage compensation by 1 week after implantation. Conversely, primordial germ cells undergo X-chromosome reactivation by reversing the XCI pathway early during their development. Our findings establish a foundation for clarifying the dosage compensation mechanisms in primates, including humans.
2021-11-19 | GSE151149 | GEO
Project description:Evolution of the mammalian sex chromosomes has resulted in a heterologous X and Y pair, where the Y chromosome has lost most of its genes. Hence, there is a need for X-linked gene dosage compensation between XY males and XX females. In placental mammals, this is achieved by random inactivation of one X chromosome (XCI) in all female somatic cells. Up-regulation of Xist transcription on the future inactive X chromosome (Xi) acts against Tsix antisense transcription, and spreading of Xist RNA in cis triggers epigenetic changes leading to XCI. Previously, we have shown that the X-encoded E3 ubiquitin ligase RNF12 is up-regulated in differentiating mouse embryonic stem cells (ESCs) and activates Xist transcription and XCI. Here, we have identified the pluripotency factor REX1 as a key target of RNF12 in the XCI mechanism. RNF12 causes ubiquitination and proteasomal degradation of REX1, and Rnf12 knockout mouse ESCs show an increased level of REX1. Using ChIP-seq, REX1 binding sites were detected in Xist and Tsix regulatory regions. Over-expression of REX1 in female ESCs was found to inhibit Xist transcription and XCI, whereas male Rex1+/- ESCs showed ectopic XCI. From this, we propose that RNF12 causes REX1 breakdown through dose-dependent catalysis, thereby representing an important pathway to initiate XCI. Rex1 and Xist are present only in placental mammals, which points to co-evolution of these two genes and XCI. 2 (one control one pulldown) samples
2012-06-12 | E-GEOD-36417 | biostudies-arrayexpress
Project description:Xist is indispensable for X chromosome inactivation (XCI) in female mammalian cells. However, how Xist RNA directs chromosome-wide transcriptional inactivation of the X chromosome is largely unknown. Here, to study chromosome inactivation by Xist, we generated a system where ectopic Xist expression can be induced from several genomic contexts in aneuploid mouse ES cells. We found that ectopic Xist expression from any location on the X chromosome faithfully recapitulated endogenous XCI, showing the potency of Xist to initiate XCI. Genes that escape XCI remain consistently transcriptionally active upon ectopic XCI, regardless of their position relative to Xist transgenes, and the enrichment of CTCF at their promoters is implicated in directing XCI escape. Xist expression from autosomes facilitates their transcriptional silencing to different degrees, and gene density in proximity of the Xist transcription locus plays a central role in determining the efficiency of gene inactivation. We also show that the enrichment of LINE elements together with a specific chromatin environment facilitates Xist-mediated silencing of both X-linked and autosomal genes. These findings provide new insights into the epigenetic mechanisms that mediate XCI and identify genomic features that promote Xist-mediated chromosome-wide gene inactivation
2017-07-04 | GSE92894 | GEO