The three-dimensional arcitecture of the EJC core

J Mol Biol. 2006 Jul 21;360(4):743-9. doi: 10.1016/j.jmb.2006.05.049. Epub 2006 Jun 5.


The exon junction complex (EJC) is a macromolecular complex deposited at splice junctions on mRNAs as a consequence of splicing. At the core of the EJC are four proteins: eIF4AIII, a member of the DExH/D-box family of NTP-dependent RNA binding proteins, Y14, Magoh, and MLN51. These proteins form a stable heterotetramer that remains bound to the mRNA throughout many different cellular environments. We have determined the three-dimensional (3D) structure of this EJC core using negative-stain random-conical tilt electron microscopy. This structure represents the first structure of a DExH/D-box protein in complex with its binding partners. The EJC core is a four-lobed complex with a central channel and dimensions consistent with its known RNA footprint of about ten nucleotides. Using known X-ray crystallographic structures and a model of three of the four components, we propose a model for complex assembly on RNA and explain how Y14:Magoh may influence eIF4AIII's RNA binding.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallography, X-Ray
  • Eukaryotic Initiation Factor-4A / chemistry
  • Eukaryotic Initiation Factor-4A / metabolism
  • Exons*
  • Gene Expression
  • Humans
  • Models, Molecular
  • Negative Staining
  • Neoplasm Proteins / chemistry
  • Neoplasm Proteins / ultrastructure
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / ultrastructure
  • Protein Binding
  • RNA Splice Sites*
  • RNA-Binding Proteins
  • Ribonucleoproteins / chemistry*
  • Ribonucleoproteins / isolation & purification
  • Ribonucleoproteins / metabolism*
  • Ribonucleoproteins / ultrastructure


  • CASC3 protein, human
  • Neoplasm Proteins
  • Nuclear Proteins
  • RNA Splice Sites
  • RNA-Binding Proteins
  • Ribonucleoproteins
  • Eukaryotic Initiation Factor-4A