DIRECT BINDING TO NUCLEIC-ACIDS BY VPR OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1

Human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) is a 15 kDa regulatory protein packaged in the HIV-1 virion. Although the molecular mechanism of Vpr function during viral replication remains e lusive, Vpr has been found to possess interesting biological activitie s, including cell-cycle arrest at the G2/M check point, promotion of t he HIV-1 pre-integration complex for nuclear transport, and a low but significant level of transcriptional activation of a variety of viral and cellular promoters. We now present data suggesting that HIV-1 Vpr is a nucleic-acid-binding protein. This activity of Vpr was demonstrat ed by DNA-cellulose chromatography, antibody co-immunoprecipitation, a nd gel electrophoretic mobility shift assays. By mutational analysis, the C-terminal region of Vpr, which is rich in basic amino-acid residu es, was shown to be critical for Vpr binding to nucleic acids. The nuc leic-acid-binding activity of Vpr is consistent with several biologica l activities of Vpr and may provide an important clue for understandin g the molecular interactions between HIV-1 and the host cells. (C) 199 8 Elsevier Science B.V. All rights reserved.