Protein Vpr, HIV2 (Vpr)

Viral protein R (Vpr) is present in the viral particle and have been found to function in the early stage of viral replication. Vpr proteins of both virions were associated with cell cycle arrest in the G2 state. While HIV-1 Vpr is associated with the nuclear localization of the preintegration complex, inhibition of cellular proliferation, and induction of differentiation, in addition to serving as a transcriptional activator of the viral genome, HIV-2 Vpr was additionally found to be necessary for efficient virus budding. The arginine-rich domain of the Vpr protein is highly conserved in the amino acid sequence of human immunodeficiency viruses, and an R78A mutation in this region was found to confer the complete loss of LTR transactivation and G2/M cell cycle arrest.