title: Tethering of human Ago proteins to mRNA mimics the miRNA-mediated repression of protein synthesis.
abstract: MicroRNAs (miRNAs) are approximately 21-nt-long RNAs involved in regulating development, differentiation, and other processes in eukaryotes. In metazoa, nearly all miRNAs control gene expression by imperfectly base-pairing with the 3'-untranslated region (3'-UTR) of target mRNAs and repressing protein synthesis by an unknown mechanism. It is also unknown whether miRNA-mRNA duplexes containing mismatches and bulges provide specific features that are recognized by factors mediating the repression. miRNAs form part of ribonucleoprotein complexes, miRNPs, that contain Argonaute (Ago) and other proteins. Here we demonstrate that effects of miRNAs on translation can be mimicked in human HeLa cells by the miRNA-independent tethering of Ago proteins to the 3'-UTR of a reporter mRNA. Inhibition of protein synthesis occurred without a change in the reporter mRNA level and was dependent on the number, but not the position, of the hairpins tethering hAgo2 to the 3'-UTR. These findings indicate that a primary function of miRNAs is to guide their associated proteins to the mRNA.
authors.affiliation: Friedrich Miescher Institute for Biomedical Research, P.O. Box 2543, 4002 Basel, Switzerland.
authors.forename: Ramesh S
authors.initials: RS
authors.lastname: Pillai
authors.forename: Caroline G
authors.initials: CG
authors.lastname: Artus
authors.forename: Witold
authors.initials: W
authors.lastname: Filipowicz
mesh_terms: D020413:3' Untranslated Regions; D060565:Argonaute Proteins; D015852:Eukaryotic Initiation Factor-2; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*
chemical_list: D020413:3' Untranslated Regions; C466422:AGO2 protein, human; D060565:Argonaute Proteins; D015852:Eukaryotic Initiation Factor-2; D035683:MicroRNAs; C421088:PIWIL1 protein, human; D010448:Peptide Initiation Factors; D011506:Proteins; D012333:RNA, Messenger