Micro Managing Translational Repression

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Science Signaling  03 Jun 2008:
Vol. 1, Issue 22, pp. ec210
DOI: 10.1126/scisignal.122ec210

MicroRNAs (miRNAs) are small noncoding RNAs that generally repress gene expression. The degree of complementarity between a miRNA and its RNA target is thought to determine the mode of repression. In plants, most characterized miRNAs are highly complementary to their targets, resulting in target cleavage (slicing), whereas those in animals have reduced complementarity and instead down-regulate mRNA translation. Brodersen et al. conducted a screen in Arabidopsis for factors involved in miRNA-mediated gene regulation and found that, in addition to directing cleavage, highly complementary miRNAs also repressed translation. Furthermore, siRNAs, which are precisely complementary to their mRNA targets and generally thought to repress gene expression by slicing, also have a translational repression component.

P. Brodersen, L. Sakvarelidze-Achard, M. Bruun-Rasmussen, P. Dunoyer, Y. Y. Yamamoto, L. Sieburth, O. Voinnet, Widespread translational inhibition by plant miRNAs and siRNAs. Science 320, 1185-1190 (2008). [Abstract] [Full Text]