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
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Ovarian function
Follicle atresia
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MicroRNA-150 promote apoptosis of ovine ovarian granulosa cells by targeting STAR gene. Zhou R et al. (2019) To better understand the function of oar-miR-150 in the ovine granulosa cells (GCs) during the estrus cycle, the five turpan sheep were selected for detection of the expression of oar-miR-150 in follicular and luteal ovaries, respectively. Then the granulosa cells treated with oar-miR-150 mimics or negative control (NC) were analyzed by qPCR to assess the expression of genes involved in steroidogenic and apoptosis. Expression of oar-miR-150 was increased in follicular phase compared with that in luteal ovaries. STAR was a target gene of miR-150 with oar-miR-150 mimic or inhibitor and luciferase reporter assay. Overexpression of oar-miR-150 promoted expression of bax, bcl2 and Casp3 expression and declined the expression of STAR, Cyp11a1 and HSD3B1 in vitro. Taken together, these results demonstrate that the oar-miR-150 promote GCs apoptosis through modifying the expression of genes involved in progesterone synthesis.//////////////////
Expression regulated by
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Ovarian localization
Oocyte
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Expression analysis of regulatory microRNAs in bovine cumulus oocyte complex and preimplantation embryos. Abd El Naby WS et al. SummaryMicroRNAs (miRNAs) are small endogenous molecules that are involved in a diverse of cellular process. However, little is known about their abundance in bovine oocytes and their surrounding cumulus cells during oocyte development. To elucidate this situation, we investigated the relative expression pattern of sets of miRNAs between bovine oocyte and the surrounding cumulus cells during in vitro maturation using miRNA polymerase chain reaction (PCR) array. Results revealed that a total of 47 and 51 miRNAs were highly abundant in immature and matured oocytes, respectively, compared with their surrounding cumulus cells. Furthermore, expression analysis of six miRNAs enriched in oocyte miR-205, miR-150, miR-122, miR-96, miR-146a and miR-146b-5p at different maturation times showed a dramatic decrease in abundance from 0 h to 22 h of maturation. The expression of the same miRNAs in preimplantation stage embryos was found to be highly abundant in early stages of embryo development and decreased after the 8-cell stage to the blastocyst stage following a typical maternal transcript profile. Similar results were obtained by localization of miR-205 in preimplantation stage embryos, in which signals were higher up to the 4-cell stage and reduced thereafter. miR-205 and miR-210 were localized in situ in ovarian follicles and revealed a spatio-temporal expression during follicular development. Interestingly, the presence or absence of oocytes or cumulus cells during maturation was found to affect the expression of miRNAs in each of the two cell types. Hence, our results showed the presence of distinct sets of miRNAs in oocytes or cumulus cells and the presence of their dynamic degradation during bovine oocyte maturation.