Mechanistic differences between HIV-1 and SIV nucleocapsid proteins and cross-species HIV-1 genomic RNA recognition.

Background: The nucleocapsid (NC) domain of HIV-1 Gag is responsible for specific recognition and packaging of genomic RNA (gRNA) into new viral particles. This occurs through specific interactions between the Gag NC domain and the Psi packaging signal in gRNA. In addition to this critical function, NC proteins are also nucleic acid (NA) chaperone proteins that facilitate NA rearrangements during reverse transcription.

Fidelity of plus-strand priming requires the nucleic acid chaperone activity of HIV-1 nucleocapsid protein.

During minus-strand DNA synthesis, RNase H degrades viral RNA sequences, generating potential plus-strand DNA primers. However, selection of the 3' polypurine tract (PPT) as the exclusive primer is required for formation of viral DNA with the correct 5'-end and for subsequent integration. Here we show a new function for the nucleic acid chaperone activity of HIV-1 nucleocapsid protein (NC) in reverse transcription: blocking mispriming by non-PPT RNAs.

Human immunodeficiency virus type 2 reverse transcriptase activity in model systems that mimic steps in reverse transcription.

Human immunodeficiency virus type 2 (HIV-2) infection is a serious problem in West Africa and Asia. However, there have been relatively few studies of HIV-2 reverse transcriptase (RT), a potential target for antiviral therapy. Detailed knowledge of HIV-2 RT activities is critical for development of specific high-throughput screening assays of potential inhibitors.