Dppa3在胚胎干细胞多能性维持及DNA甲基化调控中的作用机制

近年发现Dppa3在ES细胞中呈异质性表达，特异表达于naïve状态ES细胞，但机制不明。我们前期研究发现外源性表达Dppa3可显著降低ES细胞DNA甲基化水平、改变染色质状态、并且在不同状态ES细胞中其定位也不同，Dppa3在ES细胞中的作用及机制尚不清楚。基于此我们认为：Dppa3在ES细胞中表达及定位参与调控DNA甲基化及组蛋白修饰，进而通过影响ES细胞表观遗传状态参与多能状态维持及早期分化调控。从该假设出发，本课题首先要探究ES细胞中Dppa3调控DNA甲基化的机制；其次探明Dppa3在ES细胞内定位分布的上游调控因素；明确Dppa3细胞内定位分布与DNA甲基化和染色质状态重塑的相关性。从而全面而深入地了解Dppa3在ES细胞多能性维持和退出中的作用，为进一步深入了解ES细胞多能性及谱系分化机制提供借鉴意义。

Recently, several studies have reported that Dppa3 is heterogeneously expressed in ES cells, which specifically highly expressed in naïve pluripotent state ES cells, but the functions and mechanisms of this expression pattern are unclear. Our preliminary data showed that ectopic expression of Dppa3 significantly decreased the level of DNA methylation in ES cells, and facilitated the chromatin remodel. The location of Dppa3 in naïve state ES cells was different from that in primed state ES cells. However, the role of the localization of Dppa3 in the regulation of DNA methylation and pluripotent state need to be elucidated..The hypothesis of this project is that Dppa3 can change the binding with DNA in ES cells, help the correct distribution of DNA methylation regulators in ES cells, and finally regulate DNA methylation and chromatin structure, which in turn affects the pluripotent state of ES cells. Based on this hypothesis, we first focus on the mechanisms of Dppa3 on DNA methylation in ES cells. Then, we will identify factors regulating the localization of Dppa3 in ES cells, and get the correlation between Dppa3 localization and DNA methylation. Finally, we will explore the role of the cleavage of Dppa3 in ES cells. .We are hopeful that this project would help us to understand the role of Dppa3 in ES cells pluripotency maintenance and uncover the mechanisms of Dppa3 on the regulation of DNA methylation in ES cells. It will helpful to understand the epigenetics involved in pluripotency maintenance and lineage commitment further laying a foundation for clinical application of ES cells.