EVIDENCE FOR THE ASSOCIATION OF NEF PROTEIN WITH HIV-2 VIRIONS

HIV-Nef protein supports viral infectivity prior to proviral integrati on. This requires Nef to be present before the expression of viral gen es and suggests its delivery as part of the virion. We report here tha t the Nef proteins of HiV-2-HOM and HIV-2-ROD are associated with the virion. After the separation Of pelleted virus in st 20-60% sucrose de nsity gradient, both proteins cosedimented with the virion-associated reverse transcriptase (RT) activity at a density characteristic of ret roviral particles. Whereas Nef-2-ROD was present in the virion only as the full-length protein, HIV-2-HOM appeared as 32 and 35 kDa isoforms . The smaller isoform is identical in molecular weight tb the protein expected from proteolytic cleavage of full-length Nef-2-HOM by the vir ion-based protease. Virion-association of Nef helps to explain the rec ently redefined biological function of this regulatory protein. Copyri ght (C) 1996 Elsevier Science B.V.