Human immunodeficiency virus type 1 Vif protein binds to the Pr55Gag precursor

Abstract

The Vif protein of human immunodeficiency virus type 1 is required for productive replication in peripheral blood lymphocytes. Previous reports suggest that vif-deleted viruses are limited in replication because of a defect in the late steps of the virus life cycle. One of the remaining questions is to determine whether the functional role of Vif involves a specific interaction with virus core proteins. In this study, we demonstrate a direct interaction between Vif and the Pr55 Gag precursor in vitro as well as in infected cells. No interaction is observed between Vif and the mature capsid protein. The Pr55 Gag-Vif interaction is detected (i) in the glutathione S-transferase system, with in vitro-translated proteins demonstrating a critical role of the NC p7 domain of the Gag precursor; (ii) with proteins expressed in infected cells; and (iii) by coimmunoprecipitation experiments. Deletion of the C-terminal 22 amino acids of Vif abolishes its interaction with the Pr55 Gag precursor. Furthermore, point mutations in the C-terminal domain of Vif which have been previously shown to abolish virus infectivity and binding to cell membranes dramatically decrease the Gag-Vif interaction. These results suggest that the interaction between Vif and the Pr55 Gag precursor is a critical determinant of Vif function.

A human immunodeficiency virus type 1 protease biosensor assay using bioluminescence resonance energy transfer

“…These data support the notion that LysRS, that is part of the HIV-1 Gag assembly complex (Kleiman and Cen, 2004), can dramatically impact on Gag processing and maturation. The impact of Vif on virus maturation has been derived from earlier reports that demonstrate that Vif associates with Gag (Bouyac et al, 1997) and to genomic RNA (Zhang et al, 2000), has effects on core stability (Ohagen and Gabuzda, 2000), and directly interacts or interferes with HIV-1 PR (Baraz et al, 2002;Bardy et al, 2001). Finally, Vif has been shown to be incorporated into budding virions (Kao et al, 2003).…”

Characterization of Human Immunodeficiency Virus Type 1 vif Gene in Long-Term Asymptomatic Individuals

“…Between these regions, conserved motifs were observed, in particular the SLQXLA motif located between amino acids 144 and 149 (Oberste and Gonda, 1992) and two other motifs in the last 30 C-terminal amino acids of the Vif protein, i.e., 161 PPLPS 165 and 168 KLTEDRWN 175 . These two latter motifs are located in the domain which is in association with the plasma membrane and with the Gagprecursor (Bouyac et al, 1997;Goncalves et al, 1995). Moreover Arg and Lys residues within the C-terminal end of Vif (8 to 11 residues between the positions 157 and 192), which are the most important residues for those interactions, are largely conserved in all LTNP as well as in late progressor Vif sequences.…”

Vif and the p55 Gag Polyprotein of Human Immunodeficiency Virus Type 1 Are Present in Colocalizing Membrane-Free Cytoplasmic Complexes

“…Somewhat surprisingly, however, virions that are produced in the absence of Vif have been shown to contain a full complement of processed viral proteins (4,22,41,56)-a finding that has led to the suggestion that Vif may act by modulating the structure or conformation of virion cores or core components. In addition, there has been one report of Vif being able to interact with the p7 Gag (nucleocapsid [NC]) portion of p55 Gag , although the biological significance of this remains to be ascertained (3).…”