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The exon–exon junction complex provides a binding platform for factors involved in mRNA export and nonsense‐mediated mRNA decay
Author(s) -
Le Hir Hervé,
Gatfield David,
Izaurralde Elisa,
Moore Melissa J.
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.17.4987
Subject(s) - biology , nonsense mediated decay , rna splicing , exon , messenger rna , microbiology and biotechnology , precursor mrna , ribonucleoprotein , mature messenger rna , rna binding protein , spliceosome , heterogeneous nuclear ribonucleoprotein , messenger rnp , xenopus , nuclear export signal , rna , genetics , cell nucleus , gene , cytoplasm
We recently reported that spliceosomes alter messenger ribonucleoprotein particle (mRNP) composition by depositing several proteins 20–24 nucleotides upstream of mRNA exon–exon junctions. When assembled in vitro , this so‐called ‘exon–exon junction complex’ (EJC) contains at least five proteins: SRm160, DEK, RNPS1, Y14 and REF. To better investigate its functional attributes, we now describe a method for generating spliced mRNAs both in vitro and in vivo that either do or do not carry the EJC. Analysis of these mRNAs in Xenopus laevis oocytes revealed that this complex is the species responsible for enhancing nucleocytoplasmic export of spliced mRNAs. It does so by providing a strong binding site for the mRNA export factors REF and TAP/p15. Moreover, by serving as an anchoring point for the factors Upf2 and Upf3, the EJC provides a direct link between splicing and nonsense‐mediated mRNA decay. Finally, we show that the composition of the EJC is dynamic in vivo and is subject to significant evolution upon mRNA export to the cytoplasm.