title: Coupling of X-chromosome reactivation with the pluripotent stem cell state.
abstract: X-chromosome inactivation (XCI) in female mammals is a dramatic example of epigenetic gene regulation, which entails the silencing of an entire chromosome through a wide range of mechanisms involving noncoding RNAs, chromatin-modifications, and DNA-methylation. While XCI is associated with the differentiated cell state, it is reversed by X-chromosome reactivation (XCR) ex vivo in pluripotent stem cells and in vivo in the early mouse embryo and the germline. Critical in the regulation of XCI vs. XCR is the X-inactivation center, a multigene locus on the X-chromosome harboring several long noncoding RNA genes including, most prominently, Xist and Tsix. These genes, which sit at the top of the XCI hierarchy, are by themselves controlled by pluripotency factors, coupling XCR with the naïve pluripotent stem cell state. In this point-of-view article we review the latest findings regarding this intricate relationship between cell differentiation state and epigenetic control of the X-chromosome. In particular, we discuss the emerging picture of complex multifactorial regulatory mechanisms, ensuring both a fine-tuned and robust X-reactivation process.
authors.affiliation: Howard Hughes Medical Institute; Department of Molecular Biology; Massachusetts General Hospital; Department of Genetics; Harvard Medical School; Boston, MA USA.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Payer
authors.affiliation: Howard Hughes Medical Institute; Department of Molecular Biology; Massachusetts General Hospital; Department of Genetics; Harvard Medical School; Boston, MA USA.
authors.forename: Jeannie T
authors.initials: JT
authors.lastname: Lee
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D005260:Female; D006801:Humans; D051379:Mice; D039904:Pluripotent Stem Cells / Q000378:metabolism*; D062085:RNA, Long Noncoding / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014960:X Chromosome / Q000235:genetics; D049951:X Chromosome Inactivation
chemical_list: D062085:RNA, Long Noncoding; D014157:Transcription Factors
keywords: PRDM14; Tsix; X-chromosome reactivation; Xist; epigenetics; long noncoding RNA; pluripotency; reprogramming; stem cells