Small RNA guides for de novo DNA methylation in mammalian germ cells

Abstract

Germline genomic methylation is essential for gamete identity and integrity in mammals. The study by Kuramochi-Miyagawa and colleagues (pp. 908-917) in the previous issue of Genes & Development links the process of DNA methylation-dependent repression of retrotranspons with the presence of piwi-interacting RNAs (piRNAs) in fetal male germ cells undergoing de novo methylation. © 2008 by Cold Spring Harbor Laboratory Press.