ABSTRACT
The genome of human immunodeficiency virus type 1 (HIV-1) is significantly more complex than the genome of simple retroviruses such as ALV. The existence of the splicing commitment pathway presents retroviruses in general, and HIV-1 in particular, with a serious conundrum. The elucidation of the functional domain organization of HIV-1 Rev has provided considerable insight into the mechanism of action of the novel regulatory protein. A highly basic, arginine-rich sequence located toward the amino-terminus of Rev constitutes a nuclear localization signal and also forms the sequence-specific RNA binding domain of Rev. If Rev indeed functions as a sequence-specific nuclear RNA export factor, then one might expect that Rev would be exported to the cytoplasm along with its RRE-containing RNA target. An elegant analysis of Rev function using microinjected Xenopus oocytes has unequivocally demonstrated that Rev can directly induce the nuclear export of target RNAs from the nucleus.
