特定内源性逆转录病毒(ERVs)元件转录激活对维持早期胚胎发育十分关键，ERVs相关序列重编程不彻底和转录活性降低是导致克隆胚胎发育异常的重要因素。目前，ERVs元件及其转录产物调控胚胎发育的功能和机制尚未阐述清楚。本项目前期通过将早期胚胎转录组数据与山羊基因组中所有ERVs序列进行双向比对，筛选到了合子基因组激活过程中高效表达的ERVs元件及其转录的lncRNA。在此基础上，本项目拟利用CRISPR-Cas9系统建立ERVs调控序列敲除细胞株，利用体细胞核移植技术构建克隆胚胎，研究ERVs序列中潜在启动子和增强子对胚胎发育的调控功能；通过功能缺失和功能获得实验，筛选早期胚胎发育必须的lncRNA，并研究其调控的靶基因和通路，明确ERVs来源lncRNA的功能。从顺式作用和反式作用两个层面，阐明ERVs调控山羊早期胚胎发育的功能，对揭示山羊胚胎发育调控机制，提高体细胞克隆效率有重要意义。

Transcriptional activation of specific endogenous retroviruses (ERVs) is critical to maintain early embryonic development. The incomplete reprogramming and insufficient transcriptional activity of ERVs-related sequences is an important factor leading to abnormal development of cloned embryos. At present, the functions and mechanisms of ERVs components and their transcripts in regulating embryonic development are yet unclear. In the early stage of this project, we obtained the activated ERVs and related lncRNA by blasting the early embryonic transcriptome with all ERVs sequences in the goat genome. On the basis of this finding, this project will establish the ERVs sequence knockout cell line using CRISPR-Cas9 system, construct the cloned embryos by somatic cell nuclear transfer, and study the regulation functions of potential promoters and enhancers in the ERVs sequences on embryonic development. Screening the essential lncRNAs for early embryonic development by loss- and gain-of-function experiments and analyzing the target genes and pathways to determine the functions of ERVs-derived lncRNA. This proposal will clarify the biological functions of ERVs in regulating goat early embryo development from the two levels of cis-acting and trans-acting. The findings of this project is great significance to reveal the mechanism of goat embryo development and improve the efficiency of somatic cell nuclear transfer technology.