State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, Inner Mongolia University, Hohhot, China.
Research Center for Mammalian Reproductive Biology and Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot, China.
EMBO Rep. 2018 Dec;19(12). doi: 10.15252/embr.201846240. Epub 2018 Nov 2.
Despite the success of animal cloning by somatic cell nuclear transfer (SCNT) in many species, the method is limited by its low efficiency. After zygotic genome activation (ZGA) during mouse development, a large number of endogenous retroviruses (ERVs) are expressed, including the murine endogenous retrovirus-L (MuERVL/MERVL). In this study, we generate a series of MERVL reporter mouse strains to detect the ZGA event in embryos. We show that the majority of SCNT embryos do not undergo ZGA, and H3K27me3 prevents SCNT reprogramming. Overexpression of the H3K27me3-specific demethylase KDM6A, but not of KDM6B, improves the efficiency of SCNT Conversely, knockdown of KDM6B not only facilitates ZGA, but also impedes ectopic Xist expression in SCNT reprogramming. Furthermore, knockdown of KDM6B increases the rate of SCNT-derived embryonic stem cells from Duchenne muscular dystrophy embryos. These results not only provide insight into the mechanisms underlying failures of SCNT, but also may extend the applications of SCNT.
尽管体细胞细胞核移植（SCNT）在许多物种中的动物克隆取得了成功，但该方法的效率仍然很低。在小鼠发育过程中的合子基因组激活（ZGA）之后，大量内源性逆转录病毒（ERVs）被表达，包括小鼠内源性逆转录病毒-L（MuERVL/MERVL）。在本研究中，我们生成了一系列 MERVL 报告小鼠品系，以检测胚胎中的 ZGA 事件。我们发现大多数 SCNT 胚胎没有经历 ZGA，并且 H3K27me3 阻止了 SCNT 重编程。H3K27me3 特异性去甲基酶 KDM6A 的过表达，而不是 KDM6B 的过表达，提高了 SCNT 的效率。相反，KDM6B 的敲低不仅促进了 ZGA，而且还阻碍了 SCNT 重编程中外源 Xist 的表达。此外，KDM6B 的敲低增加了来自杜氏肌营养不良症胚胎的 SCNT 衍生胚胎干细胞的比率。这些结果不仅提供了对 SCNT 失败机制的深入了解，而且可能扩展 SCNT 的应用。
