RNA结合蛋白-RBM10调控胚胎干细胞多能性的功能和机制研究

RNA binding proteins (RBP) decide the fate of RNAs from synthesis to decay and help RNAs to act their roles, as chaperones of RNAs. Recently, systematically study of RBPs and their RNA targets have emerged. Before this work, by screening a collection of 65 RBPs in ESCs, we have identified RBM10 as a key regulator of mESC pluripotency. RBM10 can bind to Oct4 mRNA directly to maintain its stability and also can bind to a long non-coding RNA-linc1470 to mediate its negative regulation on Oct4 during ESC differentiation. We will further explore the important roles of RBM10 in maintaining mESC state and in mouse embryonic development, and also identify its target RNAs in mESC systematically. Meanwhile, we will confirm the regulatory relationship among RBM10, Oct4 and linc1470 and their biological significance in controlling mESC pluripotency. These results will help us to understand the complicated regulatory network of RBPs and their target RNAs in ESCs and also promote the study of RBPs and ncRNAs in ESCs.

RNA结合蛋白(RBP)作为RNA的重要伴侣，决定了RNA从合成到分解的命运，并协助RNA行使功能。目前，RBP及其靶RNA的系统性研究已拉开序幕。本课题前期系统性鉴定了维持胚胎干细胞（ESC）多能性的RBP，发现RBM10是ESC多能性维持所必需的，RBM10可与Oct4 mRNA直接结合维持其稳定性，同时还可与长链非编码RNA-linc1470结合，介导了ESC分化过程中linc1470对Oct4的负调控作用。基于上述发现，本项目拟深入研究RBM10在ESC多能性维持及胚胎发育中的功能；系统性鉴定RBM10在ESC中调控的靶RNA；阐明RBM10与Oct4、linc1470之间的调控关系；并明确这一调控通路在ESC自我更新及分化中的生物学意义。这些结果将加深我们理解ESC中RBP及其互作RNA所构成的调控网络，有助于推动RBP及非编码RNA在ESC中的研究。

本项目旨在揭示参与调控胚胎干细胞多能性的RNA结合蛋白(RBP)及其调控机制。我们首先系统性筛选了在胚胎干细胞（ESC）多能性退出中具有重要作用的RBP，明确了包括RBM10、hnRNPLL在内的7个RBP是胚胎干细胞退出多能性所必需的，而hnRNPLL敲除后ESC退出全能性的缺陷最为严重。hnRNPLL敲除的ESC体外体内均不能有效退出全能性，且hnRNPLL敲除小鼠表现出严重的发育缺陷及出生后死亡。机制研究表明hnRNPLL通过促进Bptf和Tbx3的外显子跳跃，及其他可变剪接事件，促进了ESC从自我更新状态中退出，进入分化程序。我们的工作也说明RBP确实在ESC功能维持及自我更新退出中发挥重要作用，研究以RBP为靶点提高ESC体外定向分化效率的方法具有重要的理论和实际意义。