title: Xist repression shows time-dependent effects on the reprogramming of female somatic cells to induced pluripotent stem cells.
abstract: Although the reactivation of silenced X chromosomes has been observed as part of the process of reprogramming female somatic cells into induced pluripotent stem cells (iPSCs), it remains unknown whether repression of the X-inactive specific transcript (Xist) can greatly enhance female iPSC induction similar to that observed in somatic cell nuclear transfer studies. In this study, we discovered that the repression of Xist plays opposite roles in the early and late phases of female iPSCs induction. Our results demonstrate that the downregulation of Xist by an isopropyl β-d-1-thiogalactopyranoside (IPTG)-inducible short hairpin RNA (shRNA) system can greatly impair the mesenchymal-to-epithelial transition (MET) in the early phase of iPSC induction but can significantly promote the transition of pre-iPSCs to iPSCs in the late phase. Furthermore, we demonstrate that although the knockdown of Xist did not affect the H3K27me3 modification on the X chromosome, macroH2A was released from the inactivated X chromosome (Xi). This enables the X chromosome silencing to be a reversible event. Moreover, we demonstrate that the supplementation of vitamin C (Vc) can augment and stabilize the reversible X chromosome by preventing the relocalization of macroH2A to the Xi. Therefore, our study reveals an opposite role of Xist repression in the early and late stages of reprogramming female somatic cells to pluripotency and demonstrates that the release of macroH2A by Xist repression enables the transition from pre-iPSCs to iPSCs.
authors: School of Life Sciences, Beijing Normal University, Beijing, China; National Institute of Biological Sciences (NIBS), Beijing, China.
authors: Qi
authors: Q
authors: Chen
authors: Shuai
authors: S
authors: Gao
authors: Wenteng
authors: W
authors: He
authors: Xiaochen
authors: X
authors: Kou
authors: Yanhong
authors: Y
authors: Zhao
authors: Hong
authors: H
authors: Wang
authors: Shaorong
authors: S
authors: Gao
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D065150:Cellular Reprogramming / Q000187:drug effects; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D005260:Female; D055785:Gene Knockdown Techniques; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D062085:RNA, Long Noncoding / Q000378:metabolism*; D013997:Time Factors; D014960:X Chromosome / Q000235:genetics; D049951:X Chromosome Inactivation / Q000187:drug effects
chemical_list: D062085:RNA, Long Noncoding; C077885:XIST non-coding RNA; D049452:Green Fluorescent Proteins; D001205:Ascorbic Acid
keywords: H3K27me3; MacroH2A; X chromosome reactivation; Xist; iPSC; pre-iPSC