A PEPTIDE DERIVED FROM THE N-TERMINAL REGION OF HIV-1 VPR PROMOTES NUCLEAR IMPORT IN PERMEABILIZED CELLS - ELUCIDATION OF THE NLS REGION OFTHE VPR

Viral protein r (Vpr), a HIV-I auxiliary protein which mediates nuclea r import of the viral preintegration complex (PIC), contains two regio ns, N- and C-terminal, which have been proposed to function as a nucle ar localization signal (NLS). We have synthesized peptides correspondi ng to both regions (designated as VprN and VprC), conjugated them to b ovine serum albumin (BSA), and tested their ability to mediate nuclear import in permeabilized cells. Only VprN, and not VprC, functioned as an active NLS and promoted translocation of the conjugate into nuclei . Nuclear import of the conjugate aas found to be energy and temperatu re dependent and was inhibited by wheat germ agglutinin (WGA). However , it did not require the addition of cytosolic factors and was not inh ibited by the prototypic SV40 large T-antigen NLS peptide. Our results show that Vpr harbours a non-conventional negatively charged NLS and therefore suggest that Vpr may use a distinct nuclear import pathway. (C) 1998 Federation of European Biochemical Societies.