An eIF4AIII-containing complex required for mRNA localization and nonsense-mediated mRNA decay

Nature. 2004 Feb 19;427(6976):753-7. doi: 10.1038/nature02351.


The specification of both the germ line and abdomen in Drosophila depends on the localization of oskar messenger RNA to the posterior of the oocyte. This localization requires several trans-acting factors, including Barentsz and the Mago-Y14 heterodimer, which assemble with oskar mRNA into ribonucleoprotein particles (RNPs) and localize with it at the posterior pole. Although Barentsz localization in the germ line depends on Mago-Y14, no direct interaction between these proteins has been detected. Here, we demonstrate that the translation initiation factor eIF4AIII interacts with Barentsz and is a component of the oskar messenger RNP localization complex. Moreover, eIF4AIII interacts with Mago-Y14 and thus provides a molecular link between Barentsz and the heterodimer. The mammalian Mago (also known as Magoh)-Y14 heterodimer is a component of the exon junction complex. The exon junction complex is deposited on spliced mRNAs and functions in nonsense-mediated mRNA decay (NMD), a surveillance mechanism that degrades mRNAs with premature translation-termination codons. We show that both Barentsz and eIF4AIII are essential for NMD in human cells. Thus, we have identified eIF4AIII and Barentsz as components of a conserved protein complex that is essential for mRNA localization in flies and NMD in mammals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Animals
  • Dimerization
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Drosophila melanogaster / genetics*
  • Drosophila melanogaster / metabolism*
  • Eukaryotic Initiation Factor-4A / metabolism*
  • Exons / genetics
  • HeLa Cells
  • Humans
  • Nuclear Proteins / metabolism
  • Protein Binding
  • Protein Biosynthesis
  • RNA Splicing
  • RNA Stability*
  • RNA Transport*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • RNA-Binding Proteins / metabolism
  • Ribonucleoproteins / genetics
  • Ribonucleoproteins / metabolism


  • Drosophila Proteins
  • MAGOH protein, human
  • Mago protein, Drosophila
  • Nuclear Proteins
  • RBM8A protein, human
  • RNA, Messenger
  • RNA-Binding Proteins
  • Ribonucleoproteins
  • btz protein, Drosophila
  • messenger ribonucleoprotein
  • osk protein, Drosophila
  • Eukaryotic Initiation Factor-4A