THE HIV-1 REV ACTIVATION DOMAIN IS A NUCLEAR EXPORT SIGNAL THAT ACCESSES AN EXPORT PATHWAY USED BY SPECIFIC CELLULAR RNAS

HIV-1 Rev protein directs nuclear export of pre-mRNAs and mRNAs contai ning its binding site, the Rev response element (RRE). To define how R ev acts, we used conjugates between bovine serum albumin (BSA) and pep tides comprising the Rev activation domain (BSA-R). BSA-R inhibited Re v-mediated nuclear RNA export, whereas a mutant activation domain pept ide conjugate did not. BSA-R did not affect the export of mRNA, tRNA, or ribosomal subunits, but did inhibit export of 5S rRNA and spliceoso mal U snRNAs. BSA-R was itself exported from the nucleus in an active, saturable manner. Thus, the Rev activation domain constitutes a nucle ar export signal that redirects RRE-containing viral RNAs to a non-mRN A export pathway.