Disease relevance of vpx

• Phosphorylation by MAPK regulates simian immunodeficiency virus Vpx protein nuclear import and virus infectivity [1].
• The vpx gene of HIV-2 was required for efficient virus propagation in PBMC, but not in an established T cell line, as previously reported [2].
• Immunoprecipitation analysis demonstrated a 16-kDa VPX protein in cells infected with SE virus, as well as in the virus particles, but not in cells infected with MX viruses or the particles themselves [3].
• Human immunodeficiency virus type 2 and the related simian immunodeficiency virus (SIV) contain a unique regulatory gene, vpx [4].
• Human immunodeficiency virus type 2 (HIV-2) is similar in genetic organization to HIV-1 but contains a unique gene (vpx) that encodes a 16-kDa protein [5].

High impact information on vpx

• These findings suggest that the VPX protein plays an important role in the in vivo life cycle of the HIV-2/SIV viruses [6].
• Here were report on the ability of four purine oligonucleotides with different lengths (11-, 14-, 17- and 20-mer) to form triplexes with the purine/pyrimidine stretch of the vpx gene [7].
• The target for the invariable part of these oligonucleotides, 5'-GGAGGGGGAGG-3', is found in a highly conserved 20 bp long purine/pyrimidine tract of the vpx gene of the SIV and HIV-2 viruses and could be a target for oligonucleotide directed antivirus therapy [7].
• Vpx protein of human immunodeficiency virus type 2/simian immunodeficiency virus (SIV) has been implicated in the transport of the viral genome into the nuclei of nondividing cells [8].
• The vpx gene products of human immunodeficiency virus type 2 (HIV-2) and of the closely related simian immunodeficiency viruses from sooty mangabeys (SIVsm) and macaques (SIVmac) comprise a 112-amino-acid virion-associated protein that is critical for efficient virus replication in nondividing cells such as macrophages [9].

Chemical compound and disease context of vpx

• Specific G2 arrest of caprine cells infected with a caprine arthritis encephalitis virus expressing vpr and vpx genes from simian immunodeficiency virus [10].

Biological context of vpx

• Deletion of the vpx gene appeared to have a greater effect on virus replication in macrophages than in PBMCs [11].
• vpx is a unique open reading frame found in simian immunodeficiency virus (SIV) and human immunodeficiency virus type 2 (HIV-2) but not in HIV-1 [12].
• This defect was localized to early events in the viral life cycle since vpx-deficient virus exhibited a 5- to 10-fold reduction in initial (single cycle) viral DNA synthesis following acute infection of primary PBMCs [13].
• Taken together, these results demonstrate that vpx is required for the production of fully infectious and cytopathic HIV-2 virions and that it functions early in the viral life cycle by facilitating viral entry and/or reverse transcription [13].
• Following transfection into immortalized T-cell lines, vpx-mutant HIV-2 was fully replication competent and exhibited growth kinetics and cytopathic properties equivalent to wild-type HIV-2 [13].

Anatomical context of vpx

• We report here that the vpx mutant of SIVmac exhibits different degrees of impairment from wild-type SIVmac in freshly isolated lymphocytes [12].
• Although vpx is dispensable for viral replication in several established human lymphocyte cell lines, there is no consensus regarding whether this gene is required for efficient viral replication in freshly isolated lymphocytes [12].
• Moreover, progeny virions from cotransfected Cos-1 cells contained wild-type amounts of vpx protein, demonstrating that vpx could be efficiently packaged in trans [14].

Associations of vpx with chemical compounds

• In this study, we generated chimeric CAEV-based genomes carrying vpr and vpx genes from SIVmac239 and tested their ability to induce G2 cell cycle arrest in infected caprine cells [10].

Analytical, diagnostic and therapeutic context of vpx

• In contrast, the vpx mutant was demonstrated to be defective at an early stage of the infection cycle in primary cell cultures [15].

References