Methylation of CpG sites of two X-linked genes coincides with X-inactivation in the female mouse embryo but not in the germ line.
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.
Grant
M
M
MRC Mammalian Development Unit, University College London, UK.
Zuccotti
M
M
Monk
M
M
D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000235:genetics*; D004303:Dosage Compensation, Genetic; D005314:Embryonic and Fetal Development / Q000235:genetics; D005260:Female; D008040:Genetic Linkage; D008297:Male; D008745:Methylation; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes / Q000737:chemistry; D016133:Polymerase Chain Reaction
D004247:DNA