title: miRNA-mediated gene silencing by translational repression followed by mRNA deadenylation and decay.
abstract: microRNAs (miRNAs) regulate gene expression through translational repression and/or messenger RNA (mRNA) deadenylation and decay. Because translation, deadenylation, and decay are closely linked processes, it is important to establish their ordering and thus to define the molecular mechanism of silencing. We have investigated the kinetics of these events in miRNA-mediated gene silencing by using a Drosophila S2 cell-based controllable expression system and show that mRNAs with both natural and engineered 3' untranslated regions with miRNA target sites are first subject to translational inhibition, followed by effects on deadenylation and decay. We next used a natural translational elongation stall to show that miRNA-mediated silencing inhibits translation at an early step, potentially translation initiation.
authors.affiliation: Howard Hughes Medical Institute (HHMI) and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Sergej
authors.initials: S
authors.lastname: Djuranovic
authors.forename: Ali
authors.initials: A
authors.lastname: Nahvi
authors.forename: Rachel
authors.initials: R
authors.lastname: Green
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D002460:Cell Line; D029721:Drosophila Proteins / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D020868:Gene Silencing; D007700:Kinetics; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D010441:Peptide Chain Elongation, Translational; D010442:Peptide Chain Initiation, Translational; D014176:Protein Biosynthesis; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*
chemical_list: D020413:3' Untranslated Regions; D029721:Drosophila Proteins; C568310:MIRN279 microRNA, Drosophila; D035683:MicroRNAs; D012333:RNA, Messenger; C471146:bantam microRNA, Drosophila