表观遗传信息在动物胚胎发育过程中的重编程

The reprogramming of epigenetic landscape during animal embryo development

表观遗传修饰调控基因的表达对胚胎发育至关重要。近期,对表观遗传修饰在跨代遗传及早期胚胎发育重编程方面的认识获得了突破性进展。在此,着重阐述DNA甲基化修饰和染色体3D结构在跨代遗传和胚胎发育过程的重编程。在斑马鱼中,子代胚胎抛弃卵子的甲基化图谱,而完全继承精子的DNA甲基化图谱;哺乳动物早期胚胎发育过程出现了全基因组去甲基化的过程,父源和母源基因组都存在主动和被动的去甲基化过程。染色体3D结构在动物受精后,TAD(topologically associated domain)结构消失,并逐渐重新建立。这些重编程对胚胎的发育过程的基因调控起着重要的作用。

Epigenomic reprogramming plays essential roles for embryonic development. Recently, significant achievements have been gained about the epigenetic inheritance during the transgenerations and the epigenetic reprogramming during early embryogenesis. Hence, we focused on the DNA methylation and 3D high-order chromatin structures. Recent studies have found that sperm but not oocyte DNA methylome is inherited by zebrafish early embryos. In mammals, there is genome-wide DNA demethylation during embryogenesis. Both paternal and maternal genomes undergo active DNA demethylation. For 3D chromatin structure, topologically associated domains disappear after fertilization, and then gradually establish during embryogenesis.