HIV proteins have various roles in the virus life cycle and pathogenesis. The viral proteins Tat, Rev, Vif, and Nef help regulate viral gene expression and replication. Tat is a transcription activator that binds TAR elements. Rev binds the RRE to allow export of unspliced viral RNA from the nucleus. Vif prevents APOBEC3G from inducing hypermutations in the viral genome. Nef downregulates CD4 and MHC to evade immune detection and promote virus spread.

1. Three possibilities after integration

9. TAT as RNAi suppressor Bennasser et al., Immunity 22, 2005, 607-619 HIV has natural intramolecular bp of 20 nt that is spliced by DICER and produced in HIV-infected cells TAT stimulates Tc but not the K41A form TAT K41A suppresses RNAi, but not K51A  Transcription activity is separate from suppression activity