Nuclear mRNA Export Requires Complex Formation between Mex67p and Mtr2p at the Nuclear Pores

Abstract

ABSTRACT We have identified between Mex67p and Mtr2p a complex which is essential for mRNA export. This complex, either isolated from yeast or assembled in Escherichia coli , can bind in vitro to RNA through Mex67p. In vivo, Mex67p requires Mtr2p for association with the nuclear pores, which can be abolished by mutating either MEX67 or MTR2 . In all cases, detachment of Mex67p from the pores into the cytoplasm correlates with a strong inhibition of mRNA export. At the nuclear pores, Nup85p represents one of the targets with which the Mex67p-Mtr2p complex interacts. Thus, Mex67p and Mtr2p constitute a novel mRNA export complex which can bind to RNA via Mex67p and which interacts with nuclear pores via Mtr2p.