Journal of General Virology

Fig. 2. Role of the Vpr–UNG complex in the HIV-1 life cycle. Virus-infected cells that express the viral proteins will accumulate HIV-1 Vpr protein complexed with the nuclear form of cellular UNG at the nucleus. Vpr–UNG complexes can then associate with the HIV-1 Gag polyprotein precursor by association of Vpr with the p6 region of Gag. The Vpr–UNG complex is incorporated into HIV-1 particles by the Vpr–Gag interaction. Virus is subsequently released from infected cells. Virus infection of a permissive cell will lead to particle disassembly and release of the virion core. The core contains many molecules, including the viral RNA, RT, Vpr, UNG and the nucleocapsid and capsid proteins. Many of these molecules in the core become the reverse transcription complex. Reverse transcription of the viral RNA occurs, after which, viral DNA and associated proteins (now called the preintegration complex) are transported to the nucleus where the viral DNA is integrated into the host cell DNA. After integration, DNA repair can occur in the provirus DNA sequence. For simplicity, incorporation of RT and other viral proteins into HIV-1 particles is not shown. Also for simplicity, only one Vpr–UNG complex is shown in particles associated with viral core.

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