在对胚胎干细胞（ESC）多能性维持的分子机制探究过程中，Erk信号通路被熟知。Erk缺失会导致多能性基因的异常表达，细胞增殖速度减慢，G1期阻滞和细胞凋亡增加，并伴随着快速的端粒缩短和基因组不稳定性。但是，Erk是如何调控ESC自我更新和端粒稳态的目前并不清楚。我们实验室前期通过蛋白质谱组学分析的方法发现了Erk2下游的重要靶蛋白，Ddx39。在小鼠ESC中Ddx39可以与Erk2相互作用，并被其磷酸化。为了进一步研究Ddx39的功能，我们构建了Ddx39敲除ESC，前期研究表明Ddx39敲除导致ESC形成克隆数目增多，端粒长度延长。下一步，我们将继续研究Ddx39敲除对ESC多能性维持和分化潜能的影响以及Ddx39的磷酸化修饰在ESC中的功能。最后我们将深入探讨，Ddx39调控ESC自我更新和端粒稳态的详细作用机制。

The Erk signaling pathway plays a key role in genomic stability and pluripotency maintenance of embryonic stem cells (ESC). It was reported that Lack of Erk led to rapid telomere shortening and genomic instability, in association with misregulated expression of pluripotency genes, reduced cell proliferation, G1 cell-cycle arrest, and increased apoptosis. However, the mechanism that how Erk regulates ESC self-renewal and telomere homeostasis is not clear. Strikingly, in this study we found the targeted protein of Erk2, Ddx39, by using Protein Mass Spectrometry (MSC) analysis. Further, this study demonstrated that Ddx39 was interacted with Erk2 and can be phosphorylated by it in ESC. To further study the function of Ddx39 in ESC, we constructed Ddx39-deleted cell lines. It has been shown that Ddx39-deficient led to an increase in the number of ESC clones and the length of telomere. Next, we will also demonstrated the function of Ddx39 in ESC pluripotency maintenance and differentiation regulation, as well as the functions of Ddx39 phosphorylation in ESC. Above all, we will continue to explore the detailed mechanisms by which Ddx39 regulates ESC self-renewal and telomere homeostasis.