Replication-coupled passive DNA demethylation for the erasure of genome imprints in mice

• DOI: 10.1038/emboj.2012.331
• Publication Date: 2012-12-14T15:18:19Z
• Authors: Saya Kagiwada; Kazuki Kurimoto; Takayuki Hirota; Masashi Yamaji; Mitinori Saitou
• Keywords: Erasure; Replication; DNA demethylation; Origin recognition complex

Genome-wide DNA demethylation, including the erasure of genome imprints, in primordial germ cells (PGCs) is a critical first step to creating a totipotent epigenome in the germ line. We show here that, contrary to the prevailing model emphasizing active DNA demethylation, imprint erasure in mouse PGCs occurs in a manner largely consistent with replication-coupled passive DNA demethylation: PGCs erase imprints during their rapid cycling with little de novo or maintenance DNA methylation potential and no apparent major chromatin alterations. Our findings necessitate the re-evaluation of and provide novel insights into the mechanism of genome-wide DNA demethylation in PGCs.