N. Kataoka et al., Magoh, a human homolog of Drosophila mago nashi protein, is a component ofthe splicing-dependent exon-exon junction complex, EMBO J, 20(22), 2001, pp. 6424-6433
The RNA-binding protein Y14 binds preferentially to mRNAs produced by splic
ing and is a component of a multiprotein complex that assembles similar to
20 nucleotides upstream of exon-exon junctions. This complex probably has i
mportant functions in post-splicing events including nuclear export and non
sense-mediated decay of mRNA. We show that Y14 binds to two previously repo
rted components, Aly/REF and RNPS1, and to the mRNA export factor TAP. More
over, we identified magoh, a human homolog of the Drosophila mago nashi gen
e product, as a novel component of the complex. Magoh binds avidly and dire
ctly to Y14 and TAP, but not to other known components of the complex, and
is found in Y14-containing mRNPs in vivo. Importantly, magoh also binds to
mRNAs produced by splicing upstream (similar to 20 nucleotides) of exon-exo
n junctions and its binding to mRNA persists after export. These experiment
s thus reveal specific protein-protein interactions among the proteins of t
he splicing-dependent mRNP complex and suggest an important role for the hi
ghly evolutionarily conserved magoh protein in this complex.