X chromosome reactivation initiates in nascent primordial germ cells in mice.
During primordial germ cell (PGC) development, epigenetic reprogramming events represented by X chromosome reactivation and erasure of genomic imprinting are known to occur. Although precise timing is not given, X reactivation is thought to take place over a short period of time just before initiation of meiosis. Here, we show that the cessation of Xist expression commences in nascent PGCs, and re-expression of some X-linked genes begins in newly formed PGCs. The X reactivation process was not complete in E14.5 PGCs, indicating that X reactivation in developing PGCs occurs over a prolonged period. These results set the reactivation timing much earlier than previously thought and suggest that X reactivation may involve slow passive steps.
Sugimoto
Michihiko
M
Technology and Development Team for Mammalian Cellular Dynamics, BioResource Center, RIKEN Tsukuba Institute, Tsukuba, Ibaraki, Japan.
Abe
Kuniya
K
D000483:Alleles; D000818:Animals; D044127:Epigenesis, Genetic; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D007700:Kinetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008957:Models, Genetic; D013997:Time Factors; D014960:X Chromosome; D049951:X Chromosome Inactivation