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Abstract：
MicroRNAs (miRNA) are important regulators of oocyte maturation, playing a key role in modulating gene expression both in a temporal- and spatial-specific manner. These small non-coding RNAs are involved in important processes during oocyte maturation, acting as messengers between the oocyte and its surrounding cumulus cells. Despite its significance, the bidirectional communication mechanism is still unknown. To test miRNA communication between oocyte and surrounding cumulus cells through the gap junctions the gap junctions were either blocked with carbenoxolone or not. MiRNA sequencing of oocytes at 1, 6, and 22 h of in vitro maturation was then performed. Among the differentially expressed miRNAs, bta-miR-21-5p, a regulator of cumulus cell viability and oocyte maturation, was the only previously known miRNA. Furthermore, by labeling a bta-miR-21-5p mimic with FAM, crossing of this miRNA through the gap junctions within the cumulus-oocyte complex could be visualized and internalization in the oocyte was confirmed by RT-qPCR. In conclusion, this study provides, for the first time, evidence that miRNA communication within the bovine cumulus-oocyte complex is enabled through the gap junctional network.
摘要：
微小RNA(miRNA)是卵母细胞成熟的重要调控因子,在以时间和空间特异性方式调节基因表达中起关键作用。这些小的非编码RNA参与卵母细胞成熟的重要过程，充当卵母细胞及其周围卵丘细胞之间的信使。尽管意义重大,双向通信机制仍然未知。为了测试卵母细胞和周围卵丘细胞之间通过间隙连接的miRNA通信,间隙连接用或不用加苯唑酮阻断。然后在体外成熟的1、6和22小时对卵母细胞进行miRNA测序。在差异表达的miRNA中，bta-miR-21-5p,卵丘细胞活力和卵母细胞成熟的调节剂，是唯一已知的miRNA。此外，通过用FAM标记bta-miR-21-5p模拟物，该miRNA通过卵丘-卵母细胞复合物内的间隙连接的交叉可以被可视化,并且通过RT-qPCR证实了卵母细胞中的内在化。总之,这项研究提供了，第一次,有证据表明，牛卵丘-卵母细胞复合物内的miRNA通讯是通过间隙连接网络实现的。
