Analysis of HIV-1 Vpr determinants responsible for cell growth arrest in <it>Saccharomyces cerevisiae</it>

• Main Authors: Yao Xiao-Jian, Rougeau Nicole, Duisit Ghislaine, Lemay Julie, Cohen Éric A
• Format: Article
• Language: English
• Published: BMC 2004-08-01
• Series: Retrovirology
• Online Access: http://www.retrovirology.com/content/1/1/21

<p>Abstract</p> <p>Background</p> <p>The HIV-1 genome encodes a well-conserved accessory gene product, Vpr, that serves multiple functions in the retroviral life cycle, including the enhancement of viral replication in nondividing macrophages, the induction of G2 cell-cycle arrest, and the modulation of HIV-1-induced apoptosis. We previously reported the genetic selection of a panel of di-tryptophan (W)-containing peptides capable of interacting with HIV-1 Vpr and inhibiting its cytostatic activity in <it>Saccharomyces cerevisiae </it>(Yao, X.-J., J. Lemay, N. Rougeau, M. Clément, S. Kurtz, P. Belhumeur, and E. A. Cohen, J. Biol. Chem. v. 277, p. 48816–48826, 2002). In this study, we performed a mutagenic analysis of Vpr to identify sequence and/or structural determinants implicated in the interaction with di-W-containing peptides and assessed the effect of mutations on Vpr-induced cytostatic activity in <it>S. cerevisiae</it>.</p> <p>Results</p> <p>Our data clearly shows that integrity of N-terminal α-helix I (17–33) and α-helix III (53–83) is crucial for Vpr interaction with di-W-containing peptides as well as for the protein-induced cytostatic effect in budding yeast. Interestingly, several Vpr mutants, mainly in the N- and C-terminal domains, which were previously reported to be defective for cell-cycle arrest or apoptosis in human cells, still displayed a cytostatic activity in <it>S. cerevisiae </it>and remained sensitive to the inhibitory effect of di-W-containing peptides.</p> <p>Conclusions</p> <p>Vpr-induced growth arrest in budding yeast can be effectively inhibited by GST-fused di-W peptide through a specific interaction of di-W peptide with Vpr functional domain, which includes α-helix I (17–33) and α-helix III (53–83). Furthermore, the mechanism(s) underlying Vpr-induced cytostatic effect in budding yeast are likely to be distinct from those implicated in cell-cycle alteration and apoptosis in human cells.</p>