RNAi-mediated knockdown of Xist can rescue the impaired postimplantation development of cloned mouse embryos

• DOI: 10.1073/pnas.1112664108
• Publication Date: 2011-11-08T06:51:56Z
• Authors: Shogo Matoba; Kimiko Inoue; Takashi Kohda; Michihiko Sugimoto; Eiji Mizutani; Narumi Ogonuki; Toshinobu Nakamura; Kuniya Abe; Toru Nakano; Fumitoshi Ishino; Atsuo Ogura
• Keywords: XIST; Cloning (programming)

Cloning mammals by somatic cell nuclear transfer (SCNT) is highly inefficient. Most SCNT-generated embryos die after implantation because of unidentified, complex epigenetic errors in the process postimplantation embryonic development. Here we identify most upstream level dysfunction leading to impaired development clones using RNAi against Xist, a gene responsible for X chromosome inactivation (XCI). A prior injection Xist-specific siRNA into reconstructed oocytes efficiently corrected SCNT-specific aberrant Xist expression at morula stage, but failed do so thereafter blastocyst stage. However, found that shortly implantation, this XCI status cloned had been autonomously both and extraembryonic tissues, probably through newly established control embryos. Embryo experiments revealed siRNA-treated showed 10 times higher survival than controls as early day 5.5 high persisted until term, resulting remarkable improvement cloning efficiency (12% vs. 1% controls). Importantly, unlike clones, these Xist-siRNA birth only limited dysregulation their expression, indicating correction preimplantation long-term effect on postnatal normality. Thus, contrary general assumption, our results suggest fate determined almost exclusively before status. Furthermore, strategy provides promising breakthrough mammalian SCNT cloning, treatment readily applicable mammal species.