Biochemical mechanism of HIV-I Vpr function. Specific interaction with a cellular protein.

Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City 66160-7424.
vpr is an accessory gene of human immunodeficiency virus I (HIV-I). Although unnecessary for viral replication in T cell lines, growing evidence suggests that it is essential for virus replication in monocytes/macrophages and for replication in vivo. We expressed HIV-I vpr in Escherichia coli and purified Vpr by affinity chromatography. In a coprecipitation assay, the purified Vpr interacted specifically with a cellular protein designated as Vpr-interacting protein, or RIP. Mutational analysis suggested that this interaction required a domain rich in leucine/isoleucine residues and highly conserved between HIV-I and SIVmac Vprs. During transient expression in mammalian cells, HIV-I Vpr was localized in the nucleus. However, mutational analysis failed to identify in Vpr a typical nuclear localization signal rich in basic amino acid residues. Instead, Vpr nuclear localization seemed to correlate with Vpr interaction with RIP. Mutations in the C-terminal 20-amino acid region containing a cryptic nuclear localization signal did not abolish Vpr nuclear localization or interaction with RIP, whereas point mutations in the leucine/isoleucine-rich domain abolished Vpr interaction with RIP and rendered Vpr unstable during transient expression. These results suggest that RIP may be involved in Vpr function.
Mesh Terms:
Amino Acid Sequence, Animals, Base Sequence, Binding Sites, Carrier Proteins, Cell Line, Cell Nucleus, Cloning, Molecular, DNA Primers, Escherichia coli, Gene Products, vpr, Genes, vpr, Genome, Viral, HIV-1, HeLa Cells, Humans, Molecular Sequence Data, Mutagenesis, Site-Directed, Oligonucleotides, Antisense, Polymerase Chain Reaction, Recombinant Proteins, Repetitive Sequences, Nucleic Acid, Restriction Mapping, Sequence Homology, Amino Acid, Transfection, vpr Gene Products, Human Immunodeficiency Virus
J. Biol. Chem. Jun. 03, 1994; 269(22);15577-82 [PUBMED:8195203]
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