HIV-1, Vpr and the cell cycle

The human immunodeficiency virus 1 (HIV-1) is a complex retrovirus with more genes than most retroviruses. One of these extra genes codes for a protein called Vpr, which has recently been shown to prevent activation of the mitotic cyclin-dependent kinase and thereby prevent infected cells from undergoing mitosis and proliferating, Vpr also plays an important role in another property of HIV-1 that is unusual for a retrovirus - its ability to enter the nucleus of a nondividing cell. Understanding the interactions between HIV 1 and the cell cycle should lead to new insights into both viral pathogenesis and basic cell biology.