MicroRNA-Mediated Regulation of Gene Expression
Lena J. Chin and Frank J. Slack
from: RNA and the Regulation of Gene Expression: A Hidden Layer of Complexity (Edited by: Kevin V. Morris). Caister Academic Press, U.K. (2008)
MiRNAs are short, ~22 nucleotide regulatory RNAs, first discovered in Caenhorhabditis elegans. Since then, hundreds of miRNAs have been identified in plants and animals. Based on the current number of predicted miRNAs, one to three percent of genomic DNA is believed to encode these small, regulatory RNAs. MiRNAs inhibit protein synthesis by binding to their target mRNAs and regulating gene expression in a post-transcriptional manner. The exact mechanism by which target gene expression is down-regulated is unclear; however, experimental evidence has led to several different theories to explain miRNA-mediated mRNA repression. These possible mechanisms include target degradation, localization to P-bodies, inhibition of translation initiation or elongation, mRNA deadenylation, and mRNA destabilization read more ...