11th Conference on Retroviruses and Opportunistic Infections San Francisco, California - February 8 - 11, 2004

Conf Retroviruses Opportunistic Infect. 2004 Feb 8-11;11th:Abstract No. 103

Nathaniel R Landau
The Salk Inst for Biological Studies, La Jolla, CA, USA

BACKGROUND: HIV-1 Vif blocks the antiviral activity of the cellular cytidine deaminase APOBEC3G/CEM15. The enzyme is encapsilated into Vif-deleted virions where it acts as a potent antiviral. The encapsilated enzyme blocks the virus lifecycle on the next round of infection by catalyzing the conversion of cytosines to uracil in the minus-strand of the viral reverse transcripts. Vif binds to APOBEC3G, preventing its encapsilation and thereby preserving the integrity of the viral genome. The interaction of Vif with APOBEC3G is species-specific such that HIV-1 Vif does not block the antiviral activity of primate or mouse APOBEC3G. Vif binds directly to human APOBEC3G but not to the mouse enzyme and only weakly to African green monkey and rhesus APOBEC3G. APOBEC3G deaminates the reverse transcripts over the entire genome at a specific tetranucleotide sequence, in a graded frequency in a direction corresponding to the predicted length of time each region is not double-stranded during reverse transcription.

CONCLUSIONS: The species-specificity of the Vif:APOBEC3G interaction is determined by a single amino acid of APOBEC3G. This amino acid appears to lie on the same face of the enzyme as the active site on an exposed loop.

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Copyright © 2004 - Foundation for Retrovirology and Human Health. Reproduction of this abstract (other than one copy for personal reference) must be cleared through the Foundation for Retrovirology and Human Health. Licensed (AIDSLINE) from National Library of Medicine.