Short-interfering-RNA-mediated gene silencing in mammalian cells requires Dicer and eIF2C translation initiation factors

Curr Biol. 2003 Jan 8;13(1):41-6. doi: 10.1016/s0960-9822(02)01394-5.


RNA interference (RNAi) is the process of long, double-stranded (ds), RNA-dependent posttranscriptional gene silencing (PTGS). In lower eukaryotes, dsRNA introduced into the cytoplasm is cleaved by the RNaseIII-like enzyme, Dicer, to 21-23 nt RNA (short interfering [si] RNA), which may serve as guide for target mRNA degradation. In mammals, long-dsRNA-dependent PTGS is applicable only to a limited number of cell types, whereas siRNA synthesized in vitro is capable of effectively inducing gene silencing in a wide variety of cells. Although biochemical and genetic analyses in lower eukaryotes showed that Dicer and some PIWI family member proteins are essential for long-dsRNA-dependent PTGS, little is known about the molecular mechanisms underlying siRNA-based PTGS. Here, we show that Dicer and eIF2C translation initiation factors belonging to the PIWI family (eIF2C1-4) play an essential role in mammalian siRNA-mediated PTGS, most probably through synergistic interactions. Immunoprecipitation experiments suggest that, in human and mouse cells, complex formation occurs between Dicer and eIF2C1 or 2 and that the PIWI domain of eIF2C is essential for the formation of this complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Amino Acid Sequence
  • Animals
  • Argonaute Proteins
  • Endoribonucleases / genetics
  • Endoribonucleases / metabolism*
  • Eukaryotic Initiation Factors*
  • Gene Silencing / physiology*
  • Genes, myc
  • HeLa Cells
  • Humans
  • Macromolecular Substances
  • Mammals / genetics
  • Mice
  • Molecular Sequence Data
  • Peptide Initiation Factors / genetics
  • Peptide Initiation Factors / metabolism*
  • Precipitin Tests
  • Protein Biosynthesis / physiology
  • RNA Interference
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / physiology*
  • Ribonuclease III


  • AGO1 protein, human
  • Argonaute Proteins
  • Eukaryotic Initiation Factors
  • Macromolecular Substances
  • Peptide Initiation Factors
  • RNA, Small Interfering
  • Endoribonucleases
  • Ribonuclease III

Associated data

  • GDB/AB028449
  • GENBANK/AB046787
  • GENBANK/AB081470
  • GENBANK/AB081471
  • GENBANK/AB081472
  • GENBANK/AB081473
  • GENBANK/AB081474