MicroRNAs direct rapid deadenylation of mRNA

Skirball Institute of Biomolecular Medicine and Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 04/2006; 103(11):4034-9. DOI: 10.1073/pnas.0510928103
Source: PubMed


MicroRNAs (miRNAs) are ubiquitous regulators of eukaryotic gene expression. In addition to repressing translation, miRNAs can down-regulate the concentration of mRNAs that contain elements to which they are imperfectly complementary. Using miR-125b and let-7 as representative miRNAs, we show that in mammalian cells this reduction in message abundance is a consequence of accelerated deadenylation, which leads to rapid mRNA decay. The ability of miRNAs to expedite poly(A) removal does not result from decreased translation; nor does translational repression by miRNAs require a poly(A) tail, a 3' histone stem-loop being an effective substitute. These findings suggest that miRNAs use two distinct posttranscriptional mechanisms to down-regulate gene expression.

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    • "The importance of small non-coding RNA, such as miRNA, for embryogenesis and development is clearly established (reviewed in Galliano and Pellicer, 2014) both in humans and in other species of interest, including pigs (Prather et al., 2009), cattle (Goossens et al., 2013) and chickens (Darnell et al., 2006). miRNA are small (18–22 nucleotides), noncoding RNA molecules that are mostly considered to be negative regulators of gene expression as they can destabilize or repress translation of messenger RNA (mRNA) (Bagga et al., 2005; Wu et al., 2006). One type of miRNA can potentially regulate more than a hundred different target genes (Lim et al., 2005). "
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