Epigenetic dynamics of imprinted X inactivation during early mouse development

Science. 2004 Jan 30;303(5658):644-9. doi: 10.1126/science.1092727. Epub 2003 Dec 11.


The initiation of X-chromosome inactivation is thought to be tightly correlated with early differentiation events during mouse development. Here, we show that although initially active, the paternal X chromosome undergoes imprinted inactivation from the cleavage stages, well before cellular differentiation. A reversal of the inactive state, with a loss of epigenetic marks such as histone modifications and polycomb proteins, subsequently occurs in cells of the inner cell mass (ICM), which give rise to the embryo-proper in which random X inactivation is known to occur. This reveals the remarkable plasticity of the X-inactivation process during preimplantation development and underlines the importance of the ICM in global reprogramming of epigenetic marks in the early embryo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Animals
  • Blastocyst / physiology
  • Blastomeres / physiology
  • Chromatin / metabolism
  • Chromosomes, Mammalian / physiology
  • Dosage Compensation, Genetic*
  • Embryo, Mammalian / physiology*
  • Embryonic and Fetal Development*
  • Epigenesis, Genetic*
  • Female
  • Genomic Imprinting*
  • Histones / metabolism
  • Male
  • Methylation
  • Mice
  • Morula / physiology
  • RNA, Long Noncoding
  • RNA, Untranslated / metabolism
  • Transcription, Genetic
  • X Chromosome / physiology*


  • Chromatin
  • Histones
  • RNA, Long Noncoding
  • RNA, Untranslated
  • XIST non-coding RNA