THE VPR PROTEIN OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 BINDS TO NUCLEOCAPSID PROTEIN P7 IN-VITRO

The Vpr protein of human immunodeficiency virus type 1 (HIV-1) is inco rporated into the virion by the Gag polyprotein precursor Pr55(gag). T he importance of the p6(gag) sequence at the C-terminal end of Pr55(ga g) has a crucial role in Vpr incorporation. To identify the Gag sequen ces directly involved in Vpr binding, we compared the Vpr binding affi nities of the 71 amino acid nucleocapsid protein p7, the C-terminal pe ptide (35-71) p7C and p6(gag) by affinity chromatography. p7 and p7C h ave the strongest Vpr binding activities compared to p6(gag). These re sults suggest that the nucleocapsid protein and its C-terminal domain may be important for the incorporation of Vpr into the mature HIV-1 vi rion and the subsequent localisation of viral nucleic acid to die cell nucleus by Vpr. (C) 1996 Academic Press, Inc.