MicroRNA

Common card · No. 238697

Micro ribonucleic acid (microRNA, miRNA, μRNA) are small, single-stranded, non-coding RNA molecules containing 21–23 nucleotides. Found in plants, animals, and even some viruses, microRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression. miRNAs base-pair to complementary sequences in messenger RNA (mRNA) molecules, then silence these mRNA molecules by one or more of the following processes: Cleaving the mRNA strand into two pieces. Destabilizing the mRNA by shortening its poly(A) tail. Reducing translation of the mRNA into proteins. In cells of humans and other animals, miRNAs primarily act by destabilizing the mRNA. miRNAs resemble the small interfering RNAs (siRNAs) of the RNA interference (RNAi) pathway, except miRNAs derive from regions of RNA transcripts that fold back on themselves to form short stem-loops (hairpins), whereas siRNAs derive from longer regions of double-stranded RNA. The human genome may encode over 1900 miRNAs. However, only about...

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