COMPLEX EVOLUTIONARY HISTORY OF PRIMATE LENTIVIRAL VPR GENES

Vpx and Vpr are homologous proteins encoded by the human and simian im munodeficiency viruses. Vpr is encoded by each of the five primate len tiviral groups, whereas Vpx is restricted to members of the HIV-2 grou p. A recent report has proposed that the vpx gene was probably acquire d from an ancestral member of the SIVagm group by nonhomologous recomb ination. Here, we suggest that this transfer event was more likely to have occurred via homologous recombination within the 3' region of ano ther gene, vif. Furthermore, phylogenetic analysis strongly suggests t hat there have been at least two other horizontal transfer events invo lving these genes: the first between ancestral members of the HIV-1 an d HIV-2 groups, and the second between viruses isolated from the verve t and tantalus subspecies of African green monkey (Cercopithecus aethi ops ssp). (C) 1998 Academic Press.