哺乳动物卵泡发育过程中，卵母细胞和卵丘细胞之间存在着复杂的双向物质信号交流过程，直接影响卵泡发育和卵子成熟，决定着繁殖效率。申请者前期在研究BMP15/GDF9—miR-375—BMPR2调控通路的过程中，进一步发现miR-187等多个miRNA靶向作用于BMPR2，circRNA可作为miRNA分子海绵参与BMPR2的转录后调控，但其机制仍不明晰。本项目在前期工作的基础上，系统识别ciRS-187—miR-187—BMPR2的相互作用位点，分析circRNA对牛卵丘细胞基因转录及蛋白表达的影响，解析其内源性竞争机制，进而揭示ciRS-187—miR-187通过BMP-Smad通路调控牛卵丘细胞增殖/凋亡、卵母细胞成熟的分子机制。研究结果将从分子层面注释牛卵丘细胞和卵母细胞的互作机制，为揭示卵母细胞成熟调控机理提供理论基础，同时可为完善体外受精、转基因、克隆等繁殖生物技术体系提供理论依据。

There is a complex two-way material signal cross-talk process between oocytes and granulosa cells, which directly affects follicular development and egg maturation and determines reproductive efficiency during the mammalian follicular development and egg maturation. In the process of studying BMP15/GDF9-BMPR2 regulatory pathway, the applicants found that multiple miRNAs such as miR-187 are targeted to BMPR2, and circRNA may be involved in post-transcriptional regulation of BMPR2, but the mechanism remains unclear. Based on the preliminary work, this project will systematically recognize the interaction site of ciRS-187-miR-187-BMPR2, analyze the effect of circRNA on gene transcription and protein expression of bovine cumulus cells, and analyze its endogenous competition mechanism and then it will be revealed that ciRS-187-miR-187 regulates the molecular mechanism of bovine cumulus cell proliferation/apoptosis and oocyte maturation through BMP-Smad pathway. The results of the study will explain the interaction mechanism between bovine cumulus cells and oocytes from the molecular level and provide a theoretical basis for revealing the regulation mechanism of oocyte maturation. Meanwhile，it will provide a theoretical basis for improving in vitro fertilization, transgenic, cloning and other reproductive biotechnology systems.