Methylation of CpG sites of two X-linked genes coincides with X-inactivation in the female mouse embryo but not in the germ line

Nat Genet. 1992 Oct;2(2):161-6. doi: 10.1038/ng1092-161.


To further our understanding of initiation and imprinting of X-chromosome inactivation, we have examined methylation of specific CpG sites of X-linked Pgk-1 and G6pd genes throughout female mouse development. Methylation occurs around the time of inactivation and earlier for Pgk-1, which is closer to the X-inactivation centre. In female primordial germ cells, the inactive X chromosome escapes methylation; this may underly the reversibility of inactivation at meiosis. Similarly, the genes are unmethylated on the inactive X chromosome in sperm; hence, the imprint specifying preferential X-inactivation in extra-embryonic tissues must reside elsewhere.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • DNA / chemistry*
  • DNA / genetics*
  • Dosage Compensation, Genetic*
  • Embryonic and Fetal Development / genetics
  • Female
  • Genetic Linkage
  • Male
  • Methylation
  • Mice
  • Molecular Sequence Data
  • Oocytes / chemistry
  • Polymerase Chain Reaction


  • DNA