10th Conference on Retroviruses and Opportunistic Infections Boston, MA USA - February 10 -14, 2003

Conf Retroviruses Opportunistic Infect 2003 Feb 10-14;10th: abstract no. 17
Christopher Aiken¹ , Donald J. Wyma¹, Janet E. Lineberger², Michael D. Miller^2
1Vanderbilt Univ Sch of Med, Nashville, TN and ²Merck Res Labs, West Point, PA

BACKGROUND: Cell entry of human immunodeficiency virus type 1 (HIV-1) particles requires a functional glycoprotein complex composed of the attachment protein gp120 and the fusion protein gp41. Proteolytic maturation of the viral core is necessary for completion of early post-entry steps in infection. Because entry of immature virions would be predicted to result in nonproductive infection, we hypothesized that the fusion activity of the HIV-1 envelope glycoprotein complex is functionally linked to HIV-1 core maturation.

METHODS: We used a novel fluorescence-based virus-cell reporter assay to quantify the fusion of HIV-1 particles arrested at various stages of core maturation. The assay employs HIV-1 particles that have incorporated beta-lactamase via fusion to Vpr. Fusion of the particles with target cells results in delivery of active beta-lactamase into target cells, resulting in cleavage of the fluorescent substrate CCF2/AM and a resulting increase in blue fluorescence.

RESULTS: Immature HIV-1 particles were markedly impaired for fusion with T-cells. Truncation of the gp41 cytoplasmic tail, pseudo-typing by VSV-G, or cleavage of the viral core precursor protein Pr55Gag between the MA and NC domains, rescued the fusion defect.

CONCLUSIONS: We have identified a novel mechanism for regulating HIV-1 entry through coupling membrane fusion activity to core maturation via binding of the gp41 cytoplasmic domain to Pr55Gag. These findings have implications for therapeutic strategies targeting HIV-1 entry and for HIV-1 vaccine development.

030210
17

Copyright © 2003 - 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.