NCBI Summary:
microRNAs (miRNAs) are short (20-24 nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. miRNAs are transcribed by RNA polymerase II as part of capped and polyadenylated primary transcripts (pri-miRNAs) that can be either protein-coding or non-coding. The primary transcript is cleaved by the Drosha ribonuclease III enzyme to produce an approximately 70-nt stem-loop precursor miRNA (pre-miRNA), which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA and antisense miRNA star (miRNA*) products. The mature miRNA is incorporated into a RNA-induced silencing complex (RISC), which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. The RefSeq represents the predicted microRNA stem-loop. [provided by RefSeq, Sep 2009]
General function
Cell proliferation, RNA processing
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Cellular localization
Cytoplasmic
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Ovarian function
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Role of microRNA-136-3p on the Expression of Luteinizing Hormone-Human Chorionic Gonadotropin Receptor mRNA in Rat Ovaries. Kitahara Y 2013 et al.
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 was involved in down-regulation of the luteinizing hormone receptor (LHR) in rat ovaries. An miRNA microarray was used to analyze the overall miRNA expression profile of rat ovaries in association with the down-regulation of LHR mRNA. We found that 23 miRNAs were highly expressed during this period. Combining these results with data from a bioinformatics database, clustering analysis led us to focus on miR-136-3p for further analysis. In both in vivo and in vitro studies, miR-136-3p levels were increased at 6 h after hCG administration, concurrent with the down-regulation of LHR mRNA. Moreover, transfection of cultured granulosa cells with miR-136-3p resulted in a significant decreased in LHR mRNA levels in comparison with those of cells transfected with negative control. In contrast, transfection with an miR-136-3p inhibitor increased LHR mRNA levels. Finally, cotransfection of granulosa cells with the miR-136-3p inhibitor and a reporter vector containing the 3'-untranslated region (UTR) of LHR mRNA and Renilla luciferase coding sequence revealed that miR-136-3p bound c to the 3'-UTR of LHR mRNA. These data demonstrated that miR-136-3p participated in the down-regulation of LHR mRNA by binding directly to LHR mRNA.
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