K. Strasser et E. Hurt, Splicing factor Sub2p is required for nuclear mRNA export through its interaction with Yra1p, NATURE, 413(6856), 2001, pp. 648-652
The yeast nuclear protein Yra1p is an essential export factor for mRNA. Yra
1p interacts directly with the mRNA transport factor Mex67p/Mtr2p, which is
associated with the nuclear pore(1,2). Here, we report a genetic interacti
on between YRA1 and SUB2, the gene for a DEAD box helicase involved in spli
cing(3-5). Mutation of SUB2 as well as its overexpression leads to a defect
in mRNA export. Moreover, Yra1p and Sub2p bind directly to each other both
in vivo and in vitro. Significantly, Sub2p and Mex67p/Mtr2p bind to the sa
me domains of Yra1p, and the proteins compete for binding to Yra1p. Togethe
r, these data indicate that the spliceosomal component Sub2p is also import
ant in mRNA export and may function to recruit Yra1p to the mRNA. Sub2p may
then be displaced from Yra1p by the binding of Mex67p/Mtr2p, which partici
pates in the export of mRNA through the nuclear pores.