新型小非编码RNA U3-sd RNA在胚胎干细胞多能性建立中的作用及其在人囊胚发育中的意义

囊胚的形成是人胚早期发育中的重要阶段，特别是内细胞团的形成及胚胎干细胞（ESC）多能性建立至关重要，而其中的特有分子调控模式有待阐明。本项目组在前期研究中发现了一种人ESC中特有的新型小非编码RNA（U3-sd RNA），其衍生于小核仁RNA U3且在稳定维持状态ESC中高表达，预实验提示U3-sd RNA可以直接参与调控人ESC多能性因子表达，其缺失可影响ESC克隆形成，同时U3-sd RNA在未分化ESC外泌体中高丰度存在。因此，本项目拟综合运用RNA体外切割、CRISPR/Cas9靶向敲除、外泌体等研究技术，分析新发现的U3-sd RNA在人囊胚和ESC中的表达特征，鉴定其加工生成机理及对多能性因子的表达调控机制，以及外泌体介导的U3-sd RNA在囊胚期细胞间通讯机制及ESC发育中的意义，从而鉴定影响人囊胚发育与ESC形成的新机制，并为胚胎发育无创性评估等技术研究提供有价值的参考。

The formation of endocyte mass and the development of embryonic stem cells (ESC) is a key stage in the early development of human embryos. Especially, the specific molecular regulation pattern of ESC deserves attention. Our group found that a novel small non-coding RNA derived from snoRNA U3 (U3-sd RNA) had a high abundance in the maintening ESC, with a very low expression levels in the differentiated ESC and other types of human cells. Preliminary experiments further suggest that U3-sd RNA is mainly located in the cytoplasm, and the mutation of specific sequences on the region of U3 can abolish the processing of U3-sd RNA. U3-sd RNA suppression can also lead to the deceased of core transcription factors in ESCs, and the loss of maintaining ability. It was also found that U3-sd RNA was highly abundant in ESC-derived exosomes and could be transferred between ESC populations. Employing the RNA pulldown, RIP and CRISPR/Cas9 targeted knockout techniques, this project intends to investigate the expression pattern and processing mechanism of U3-sd RNA in human ESC, and its role in the ESC development and cell-cell communications of inner cell mass. This project may be helpful to clarify the specific molecular regulatory mechanism in human ESC, and provides valuable reference for the mechanism of human embryos early development and non-invasive evaluation of human embryos.