MicroRNA-dependent localization of targeted mRNAs to mammalian P-bodies

Nat Cell Biol. 2005 Jul;7(7):719-23. doi: 10.1038/ncb1274. Epub 2005 Jun 5.


Small RNAs, including small interfering RNAs (siRNAs) and microRNAs (miRNAs) can silence target genes through several different effector mechanisms. Whereas siRNA-directed mRNA cleavage is increasingly understood, the mechanisms by which miRNAs repress protein synthesis are obscure. Recent studies have revealed the existence of specific cytoplasmic foci, referred to herein as processing bodies (P-bodies), which contain untranslated mRNAs and can serve as sites of mRNA degradation. Here we demonstrate that Argonaute proteins--the signature components of the RNA interference (RNAi) effector complex, RISC--localize to mammalian P-bodies. Moreover, reporter mRNAs that are targeted for translational repression by endogenous or exogenous miRNAs become concentrated in P-bodies in a miRNA-dependent manner. These results provide a link between miRNA function and mammalian P-bodies and suggest that translation repression by RISC delivers mRNAs to P-bodies, either as a cause or as a consequence of inhibiting protein synthesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3' Untranslated Regions / genetics
  • 3' Untranslated Regions / metabolism
  • Argonaute Proteins
  • Caenorhabditis elegans Proteins / genetics
  • Cell Line
  • Cell Line, Tumor
  • Cytoplasmic Structures / metabolism*
  • Endoribonucleases / metabolism
  • Eukaryotic Initiation Factor-2
  • Gene Expression Regulation
  • HeLa Cells
  • Humans
  • Immunoprecipitation
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Microscopy, Fluorescence
  • Mutation / physiology
  • Peptide Initiation Factors / genetics
  • Peptide Initiation Factors / metabolism
  • Protein Binding
  • RNA Transport
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • RNA-Induced Silencing Complex / metabolism
  • Receptors, CXCR4 / genetics
  • Trans-Activators / metabolism
  • Transfection


  • 3' Untranslated Regions
  • AGO2 protein, human
  • Argonaute Proteins
  • Caenorhabditis elegans Proteins
  • Eukaryotic Initiation Factor-2
  • MicroRNAs
  • Peptide Initiation Factors
  • RNA, Messenger
  • RNA, Small Interfering
  • RNA-Induced Silencing Complex
  • Receptors, CXCR4
  • Trans-Activators
  • let-7 microRNA, C elegans
  • Endoribonucleases
  • DCP1A protein, human
  • DCP2 protein, human