Role of micro RNA on the Expression of Luteinizing Hormone-Human Chorionic Gonadotropin Receptor Messenger Ribonucleic Acid in rat ovary

微小RNA（microRNAs，miRNAs）是一类与mRNA相互作用的非编码小分子RNA，它可以引起靶基因的翻译抑制或RNA切割。在这项研究中，我们研究了miRNA是否参与卵巢LH受体（LHR）的下调。利用miRNA微阵列分析LHR mRNA下调过程中的总体miRNA表达谱，发现在此期间有23个miRNA高表达。将这些结果与来自生物信息数据库的数据相结合，聚类分析使我们专注于miR-136* 进行进一步分析。在体内和体外研究中，发现miR-136* 水平在hCG给药后6小时增加，而LHR mRNA水平下调。为了证实miR-136* 与LHR mRNA结合，我们将LHR mRNA的3 '端从2570至2895克隆到报告载体中，该报告载体在克隆位点上游含有海肾荧光素酶编码区。当miR-136* 抑制剂与报告载体在颗粒细胞中共转染时，荧光素酶活性被去抑制，表明miR-136* 明确结合于LHR mRNA的3 '端。根据这些数据，我们得出结论，miR-136* 参与LHR mRNA的下调机制，从而miR-136* 与LHR mRNA形成碱基对。

MicroRNAs (miRNAs) are small non-coding RNAs that interact with mRNAs and trigger either translation repression or RNA cleavage of target genes. In this study, we investigated whether miRNA is involved in down-regulation of the LH receptor (LHR) in the ovary. A miRNA microarray was carried out to analyze the overall miRNA expression profile while LHR mRNA was down-regulated, and found that 23 miRNAs were highly expressed during this period. Combining these results with data from the bioinformative database, the clustering analysis led us to focus on miR-136* for further analysis. In both in vivo and in vitro studies, miR-136* levels were found to increase 6 hr after hCG administration while LHR mRNA levels were down-regulated. To confirm that miR-136* binds to LHR mRNA, we cloned the 3'-end of LHR mRNA from 2570 to 2895 into reporter vector which contained a Renilla luciferase coding region upstream of the cloning site. When the miR-136* inhibitor was co-transfected with the reporter vector in granulosa cells, the luciferase activity was de-repressed, revealing that miR-136* definitely bound to the 3'-end of LHR mRNA. From these data, we conclude that miR-136* participates in the mechanism of down-regulation of LHR mRNA, whereby miR-136* forms base pairs with LHR mRNA.