已有 3265 次阅读 2013-9-23 22:09 |个人分类:epigenetics|系统分类:科研笔记

A set of genes critical to development is epigenetically poised in mouse germ cells from fetal stages through completion of meiosis.


In multicellular organisms, germ cells carry the hereditary material from one generation to the next. Developing germ cells are unipotent gamete precursors, and mature gametes are highly differentiated, specialized cells. However, upon gamete union at fertilization, their genomes drive a totipotent program, giving rise to a complete embryo as well as extraembryonic tissues. The biochemical basis for the ability to transition from differentiated cell to totipotent zygote is unknown. Here we report that a set of developmentally critical genes is maintained in an epigenetically poised (bivalent) state from embryonic stages through the end of meiosis. We performed ChIP-seq and RNA-seq analysis on flow-sorted male and female germ cells during embryogenesis at three time points surrounding sexual differentiation and female meiotic initiation, and then extended our analysis to meiotic and postmeiotic male germ cells. We identified a set of genes that is highly enriched for regulators of differentiation and retains a poised state (high H3K4me3, high H3K27me3, and lack of expression) across sexes and across developmental stages, including in haploid postmeiotic cells. The existence of such a state in embryonic stem cells has been well described. We now demonstrate that a subset of genes is maintained in a poised state in the germ line from the initiation of sexual differentiation during fetal development and into postmeiotic stages. We propose that the epigenetically poised condition of these developmental genes is a fundamental property of the mammalian germ-line nucleus, allowing differentiated gametes to unleash a totipotent program following fertilization.

Fig. 1. ChIP-seq and RNA-seq data reflect the known biology of mouse fetal germ cells. (A) Sample gene tracks showing biological replicates of female E13.5 H3K4me3 and H3K27me3 data. (B) Correlated changes between H3K4me3 ChIP signal and gene expression for three core pluripotency regulators (Oct4, Sox2, and Nanog) and three genes associated with meiotic initiation (Stra8, Rec8, and Sycp3).



该博文允许注册用户评论 请点击登录 评论 (0 个评论)


Archiver|手机版|科学网 ( 京ICP备07017567号-12 )

GMT+8, 2022-5-19 01:24

Powered by

Copyright © 2007- 中国科学报社