MIR133B, Official Symbol MIR133Bprovided by HGNC Official Full Name microRNA 133bprovided by HGNC Primary source HGNC:HGNC:31759 See related Ensembl:ENSG00000199080 MIM:610946; miRBase:MI0000822; AllianceGenome:HGNC:31759 Gene type ncRNA RefSeq status PROVISIONAL Organism Homo sapiens Lineage Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo Also known as MIRN133B; mir-133b; miRNA133B 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 encoded miRNA is considered a canonical myomiR and is important for normal cardiac and skeletal muscle development. It is additionally important for normal development in non-muscle tissues, and is abnormally expressed in a variety of cancers. The RefSeq represents the predicted microRNA stem-loop. [provided by RefSeq, Sep 2017]