近年来的研究发现小鼠胚胎干细胞群体中会自发地产生具有早期胚胎发育二细胞(2C)时期全能性细胞分子特征的稀有细胞亚群，并且这种2C样细胞既能发育成胚胎组织，也能产生胚外组织，因而对基础研究和再生医学研究均有重要的意义。本研究将以2C样细胞为模型，系统地筛选可以使多能干细胞获得全能性特征的表观遗传调控因子和转录因子，并综合运用DNA修饰、组蛋白修饰以及染色质三维结构、mRNA poly(A)尾长度等多组学分析手段深入研究多能干细胞获得2C样全能性特征的表观遗传学分子基础和调控机制。本项目旨在加深人们对细胞全能性和胚胎发育最早期细胞命运调控的理解，并探索建立体外诱导、培养和扩增具有类似2C样全能性特征的潜能扩展性干细胞的新方法，还将探索人源多能干细胞如何获得4C样全能性特征。这项研究将有助于理解人类的正常早期发育及发育相关疾病，并为组织工程和再生医学等实践积累新知识、提出新理论、创建新方法。

Mouse embryonic stem cells (ESCs) are pluripotent but not totipotent, as they only give rise to cells in the embryonic lineage, but not the extra-embryonic lineages. While the gene regulatory network underlying pluripotency is well studied, how the totipotent state is regulated remains to be elucidated. Recently, it has been shown that a rare transient cell population within mouse ESCs expresses high levels of transcripts found in the two-cell (2C) embryos in which both the two blastomeres are totipotent. More importantly, these 2C-like cells can contribute to both embryonic and extra-embryonic tissues and are therefore important for both basic research and translational research. Here, using 2C-like cells as a model, we will perform both CRISPR-Cas9 knockout screen and transcription activation screen for epigenetic regulators and transcription factors that regulate the entering and exiting of 2C-like state. Moreover, we will profile genome-wide DNA/histone modifications, 3D chromatin structure and lengths of mRNA poly(A) in 2C-like cells to understand the epigenetic mechanisms. We will also explore whether a rare 4C-like population exists in human naïve ESCs. Our study will not only contribute to a better understanding of how the totipotent state during early development is established but also allow for the development of techniques and approaches that will improve regeneration medicine.