X chromosome reactivation dynamics reveal stages of reprogramming to pluripotency

Cell. 2014 Dec 18;159(7):1681-97. doi: 10.1016/j.cell.2014.11.040.

Abstract

Reprogramming to iPSCs resets the epigenome of somatic cells, including the reversal of X chromosome inactivation. We sought to gain insight into the steps underlying the reprogramming process by examining the means by which reprogramming leads to X chromosome reactivation (XCR). Analyzing single cells in situ, we found that hallmarks of the inactive X (Xi) change sequentially, providing a direct readout of reprogramming progression. Several epigenetic changes on the Xi occur in the inverse order of developmental X inactivation, whereas others are uncoupled from this sequence. Among the latter, DNA methylation has an extraordinary long persistence on the Xi during reprogramming, and, like Xist expression, is erased only after pluripotency genes are activated. Mechanistically, XCR requires both DNA demethylation and Xist silencing, ensuring that only cells undergoing faithful reprogramming initiate XCR. Our study defines the epigenetic state of multiple sequential reprogramming intermediates and establishes a paradigm for studying cell fate transitions during reprogramming.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cdh1 Proteins / metabolism
  • Cellular Reprogramming*
  • DNA Methylation
  • Epigenesis, Genetic*
  • Homeodomain Proteins / metabolism
  • Induced Pluripotent Stem Cells / cytology*
  • Induced Pluripotent Stem Cells / metabolism*
  • Mice
  • Nanog Homeobox Protein
  • RNA, Long Noncoding / metabolism
  • X Chromosome / metabolism*

Substances

  • Cdh1 Proteins
  • Fzr1 protein, mouse
  • Homeodomain Proteins
  • Nanog Homeobox Protein
  • Nanog protein, mouse
  • RNA, Long Noncoding
  • Tsix transcript, mouse

Associated data

  • GEO/GSE58109