microRNAs, or 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
polyadenylatedprimary 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].
Chen ZX, Sun AM, Chen Y, Liu Y, Zhan JF, Chen LH, Yuan YW (August 2010). "[Effects of radiosensitivity and X-ray dose on miR-7 expression in nasopharyngeal carcinoma]". Nan Fang Yi Ke da Xue Xue Bao = Journal of Southern Medical University. 30 (8): 1810–2, 1816.
PMID20813671.