oocyte marker?
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
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Cellular localization
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Ovarian function
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MiR-202-5p is a novel germ plasm-specific microRNA in zebrafish. Zhang J et al. (2017) Gametogenesis is a complicated biological process by which sperm and egg are produced for genetic transmission between generations. In many animals, the germline is segregated from the somatic lineage in early embryonic development through the specification of primordial germ cells (PGCs), the precursors of gametes for reproduction and fertility. In some species, such as fruit fly and zebrafish, PGCs are determined by the maternally provided germ plasm which contains various RNAs and proteins. Here, we identified a germ plasm/PGC-specific microRNA miR-202-5p for the first time in zebrafish. MiR-202-5p was specifically expressed in gonad. In female, it was expressed and accumulated in oocytes during oogenesis. Quantitative reverse transcription PCR and whole mount in situ hybridization results indicated that miR-202-5p exhibited a typical germ plasm /PGC-specific expression pattern throughout embryogenesis, which was consistent with that of the PGC marker vasa, indicating that miR-202-5p was a component of germ plasm and a potential PGC marker in zebrafish. Our present study might be served as a foundation for further investigating the regulative roles of miRNAs in germ plasm formation and PGC development in zebrafish and other teleost.//////////////////
Expression regulated by
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Ovarian localization
Primordial Germ Cell, Oocyte
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Manipulation of Estrogen Synthesis Alters MIR202* Expression in Embryonic Chicken Gonads. Bannister SC et al. Tissue-specific patterns of microRNA (miRNA) expression contribute to organogenesis during embryonic development. Using the embryonic chicken gonads as a model for vertebrate gonadogenesis, we previously reported that miRNAs are expressed in a sexually-dimorphic manner during gonadal sex differentiation. Being male-biased, we hypothesised that up-regulation of microRNA 202* (MIR202*) is characteristic of testicular differentiation. To address this hypothesis, we used estrogen modulation to induce gonadal sex-reversal in embryonic chicken gonads and analyzed changes in MIR202* expression. In ovo injection of estradiol-17beta at Embryonic Day 4.5 (E4.5) caused feminization of male gonads at E9.5 and reduced MIR202* expression to female levels. Female gonads treated at E3.5 with an Aromatase inhibitor, which blocks estrogen synthesis, were masculinized by E9.5 and MIR202* expression was increased. Reduced MIR202* expression correlated with reduced expression of the testis-associated genes DMRT1 and SOX9, and up-regulation of ovary-associated genes FOXL2 and CYP19A1 (aromatase). Increased MIR202* expression correlated with down-regulation of FOXL2 and aromatase and up-regulation of DMRT1 and SOX9. These results confirm that up-regulation of MIR202* coincides with testicular differentiation in embryonic chicken gonads.