Argonaute loading improves the 5' precision of both MicroRNAs and their miRNA strands in flies
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UMass Chan Affiliations
Department of Biochemistry and Molecular PharmacologyDocument Type
Journal ArticlePublication Date
2008-01-22Keywords
Animals; Cell Line; Drosophila Proteins; Drosophila melanogaster; MicroRNAs; RNA-Induced Silencing Complex; Ribonuclease IIILife Sciences
Medicine and Health Sciences
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MicroRNAs (miRNAs) are short regulatory RNAs that direct repression of their mRNA targets. The miRNA "seed"-nucleotides 2-7-establishes target specificity by mediating target binding. Accurate processing of the miRNA 5' end is thought to be under strong selective pressure because a shift by just one nucleotide in the 5' end of a miRNA alters its seed sequence, redefining its repertoire of targets (Figure 1). Animal miRNAs are produced by the sequential cleavage of partially double-stranded precursors by the RNase III endonucleases Drosha and Dicer, thereby generating a transitory double-stranded intermediate comprising the miRNA paired to its partially complementary miRNA strand. Here, we report that in flies, the 5' ends of miRNAs and miRNA strands are typically more precisely defined than their 3' ends. Surprisingly, the precision of the 5' ends of both miRNA and miRNA sequences increases after Argonaute2 (Ago2) loading. Our data imply that either many miRNA sequences are under evolutionary pressure to maintain their seed sequences-that is, they have targets-or that secondary constraints, such as the sequence requirements for loading small RNAs into functional Argonaute complexes, narrow the range of miRNA and miRNA 5' ends that accumulate in flies.Source
Curr Biol. 2008 Jan 22;18(2):147-51. Link to article on publisher's siteDOI
10.1016/j.cub.2007.12.049Permanent Link to this Item
http://hdl.handle.net/20.500.14038/33058PubMed ID
18207740Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1016/j.cub.2007.12.049