Identification and localization of vpr gene product of human immunodeficiency virus type 1

The entire vpr gene of human immunodeficiency virus type 1 (HIV-1) was cloned into procaryotic and eucaryotic expression vectors. Production of authentic protein encoded by the gene in bacterial and mammalian cells was monitored by Western blotting using guinea pig antisera raised against an N-terminal 14-oligopeptide of the predicted vpr protein. A specific 12-kD protein was clearly detected with these antisera, but not with preimmune sera, in both cell systems, and this binding was blocked by the oligopeptide. These antisera also recognized a protein of the same size in several human T-cell lines infected with HIV-1. Western blotting analysis of subcellular fractions prepared from the cells producing wildtype vpr protein strongly suggested that the protein was membrane associated. A region within the vpr required for the stable expression of vpr product was also suggested by mutational analyses.