Dynamic Erasure of Random X-Chromosome Inactivation during iPSC Reprogramming
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ABSTRACT:
PROVIDER: PRJNA521357 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR8545480_1.fastq.gz | Fastqsanger.gz | |||
| SRR8545480_2.fastq.gz | Fastqsanger.gz | |||
| SRR8545481_1.fastq.gz | Fastqsanger.gz | |||
| SRR8545481_2.fastq.gz | Fastqsanger.gz | |||
| SRR8545482_1.fastq.gz | Fastqsanger.gz |
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Project description:Induction and reversal of chromatin silencing is critical for successful development, tissue homeostasis and the derivation of induced pluripotent stem cells (iPSCs). X-chromosome inactivation (XCI) and reactivation (XCR) in female cells represent chromosome-wide transitions between active and inactive chromatin states. While XCI has long been studied and provided important insights into gene regulation, the dynamics and mechanisms underlying the reversal of stable chromatin silencing of X-linked genes are much less understood. In this work, we use allele-resolution transcriptomic approaches to study XCR during mouse iPSC reprogramming in order to elucidate the timing and mechanisms of chromosome-wide reversal of gene silencing. Our findings reveal a sequential hierarchy of gene reactivation from the inactive X-chromosome (Xi). We show that gene reactivation initiates before the activation of late pluripotency genes and complete silencing of the long non-coding RNA (lncRNA) Xist, and is completed late in reprogramming. We reveal that the gene-specific timing of reactivation correlates with the genomic distance to genes that escape inactivation and with differential targeting by pluripotency transcription factors (TFs). We also show that histone deacetylases restrict XCR in reprogramming intermediates and that the severe hypoacetylation state of the Xi persists until late reprogramming stages. Therefore, randomly inactivated X-linked genes possess different degrees of epigenetic memory, the reversal of which may involve the combined action of chromatin regulators, pluripotency transcription factors and chromatin topology. Taken together, our study provides the chromosome-wide dynamics of gene reactivation from the randomly inactivated X-chromosome and a framework for understanding how transcription factors induce dynamic reversal of stable epigenetic memory by overcoming repressive chromatin barriers.
2019-02-08 | GSE126229 | GEO
Project description:Induction and reversal of chromatin silencing is critical for successful development, tissue homeostasis, and the derivation of induced pluripotent stem cells (iPSCs). X-Chromosome inactivation (XCI) and reactivation (XCR) in female cells represent chromosome-wide transitions between active and inactive chromatin states. Although XCI has long been studied, providing important insights into gene regulation, the dynamics and mechanisms underlying the reversal of stable chromatin silencing of X-linked genes are much less understood. Here, we use allele-specific transcriptomics to study XCR during mouse iPSC reprogramming in order to elucidate the timing and mechanisms of chromosome-wide reversal of gene silencing. We show that XCR is hierarchical, with subsets of genes reactivating early, late, and very late during reprogramming. Early genes are activated before the onset of late pluripotency genes activation. Early genes are located genomically closer to genes that escape XCI, unlike genes reactivating late. Early genes also show increased pluripotency transcription factor (TF) binding. We also reveal that histone deacetylases (HDACs) restrict XCR in reprogramming intermediates and that the severe hypoacetylation state of the inactive X Chromosome (Xi) persists until late reprogramming stages. Altogether, these results reveal the timing of transcriptional activation of monoallelically repressed genes during iPSC reprogramming, and suggest that allelic activation involves the combined action of chromatin topology, pluripotency TFs, and chromatin regulators. These findings are important for our understanding of gene silencing, maintenance of cell identity, reprogramming, and disease.
| S-EPMC6771397 | biostudies-literature
Project description:Imprinted X-inactivation is a paradigm of transgenerational epigenetic inheritance in mammals and silences genes exclusively on the paternally-inherited X-chromosome. Here, we test the hypothesis that oocyte-derived maternal Polycomb repressive complex 2 (PRC2) protein EED orchestrates the selective inactivation of the paternal-X in mouse embryos. In maternal Eed null (Eedm-/-) but not zygotic Eed null female and male embryos, the maternal X-chromosome ectopically induced Xist lncRNA, which silences X-linked genes. Subsequently, Xist was silenced from one of the two X-chromosomes in females and from the sole maternal-X in males. As a result, later-stage female Eedm-/- embryos displayed random X-inactivation. The kinetics of Xist RNA induction in Eedm-/- embryos resemble that of early human embryos, which lack oocyte-derived PRC2 and only undergo random X-inactivation. Thus, expression of PRC2 genes in the oocyte and transmission of the gene products to the embryo may dictate the occurrence of imprinted X-inactivation in mammals.
2019-05-02 | GSE123173 | GEO
Project description:To ensure dosage compensation between the sexes, one randomly chosen X chromosome is silenced in each female cell in the process of X-chromosome inactivation (XCI). XCI is a model for cellular decision making and epigenetic gene regulation. The random cell-autonomous nature of XCI however has so far prevented its chromosome-wide investigation in its endogenous context without genetic perturbation. Here we use allele-specific single-cell RNA-sequencing to assess the onset of random XCI with high temporal resolution in differentiating mouse embryonic stem cells, and develop dedicated analysis approaches. We find that XCI is initiated on both chromosomes in a subset of cells, but reverted to the final mono-allelic state once gene silencing is established. By exploiting the heterogeneity of XCI onset, we identify Nanog as its main trigger and discover additional genes that might control upregulation of Xist, the master regulator of XCI. Finally, we show that genetic variation between different mouse strains modulates the XCI process at multiple levels, and validate these findings through an orthogonal experimental approach. We thus draw a detailed picture of how XCI is initiated and the experimental and computational strategies we have developed here will now allow us to profile random XCI in more physiological contexts, including primary human cells in vivo.
2020-05-22 | GSE151009 | GEO
Project description:Switching from Random to Imprinted X-inactivation by Maternal PRC2
| PRJNA507766 | ENA
Project description:Dissecting the onset of random X-chromosome inactivation at high temporal and allelic resolution
| PRJNA634366 | ENA
Project description:Xist-mediated Chromosome Inactivation
| PRJNA489702 | ENA
Project description:Spen regulates X chromosome inactivation
| PRJNA544935 | ENA
Project description:BACKGROUND:X chromosome inactivation (XCI) is an indispensable process in the development of human female embryos. Reportedly, XCI occurs when a blastocyst contains 10-12 embryonic progenitor cells. To date, it remains unclear whether XCI ratios are normally preserved in Klinefelter syndrome (KS) patients with 47,XXY karyotype. METHODS:We examined XCI ratios in 18 KS patients through DNA methylation analysis for the polymorphic trinucleotide locus in the AR gene. The results of the KS patients were compared to previous data from healthy young women. RESULTS:XCI ratios in KS patients followed a normal distribution. Skewed XCI was observed in two patients, one of whom exhibited extremely skewed XCI. The frequencies of skewed and extremely skewed XCI in the KS cohort were comparable to those in healthy women. CONCLUSION:This study confirmed the rarity of skewed XCI in KS patients. These results indicate that the presence of a supernumerary X chromosome during the cleavage and early blastocyst stages does not affect the developmental tempo of embryos. Our data deserve further validation.
| S-EPMC6979883 | biostudies-literature
Project description:Genomic imprinting is essential for mammalian development. Recent studies have revealed that maternal histone H3 lysine 27 tri-methylation (H3K27me3) can mediate DNA methylation-independent genomic imprinting. However, the regulatory mechanisms and functions of this new imprinting mechanism are largely unknown. Here we demonstrate that maternal Eed, an essential component of the Polycomb group complex 2 (PRC2), is required for establishing H3K27me3 imprinting. We found that all H3K27me3 imprinted genes, including Xist, lose their imprinted expression in Eed maternal KO (matKO) embryos, resulting in male-biased lethality. Surprisingly, although maternal X chromosome inactivation (XmCI) occurs in Eed matKO embryos at preimplantation due to loss of Xist imprinting, it is resolved at peri-implantation. Ultimately, both X chromosomes are reactivated in the embryonic cell lineage prior to random XCI, and only a single X chromosome undergoes random XCI in the extra-embryonic cell lineage. Thus, our study not only demonstrates an essential role of Eed in H3K27me3 imprinting establishment but also reveals a unique XCI dynamics in the absence of Xist imprinting.
2018-11-26 | GSE116713 | GEO