IDENTIFICATION OF A NOVEL NUCLEAR PORE-ASSOCIATED PROTEIN AS A FUNCTIONAL TARGET OF THE HIV-1 REV PROTEIN IN YEAST

The HIV-1 Rev protein increases the cytoplasm ic levels of unspliced a nd singly spliced target transcripts in metazoan systems. Based on exp eriments that indicate a similar function of Rev in the yeast S. cerev isiae, we have identified a yeast protein that interacts with the effe ctor domain of Rev. The protein, Rip1p, is a novel small nucleoporin-l ike protein, some of which is associated with nuclear pores. Its close st known yeast relative is a nuclear pore component also implicated in mRNA transport from nucleus to cytoplasm. Analysis of strains that ov erexpress Rip1p or that are deleted for the RIP1 gene show that Rip1p is important for the effect of Rev on gene expression, indicating that the physical interaction is of functional significance in vivo. The r esults suggest that Rev directly promotes the cytoplasmic transport of suitable transcripts by targeting them to the nuclear pore.