Fig. 2.

Most HIV-1 primary Vpr variants can efficiently induce a G₂ cell cycle arrest in T cells. CEM.NKR T cells were transduced with GFP-marked lentiviral vectors expressing Vpr (primary laboratory-adapted [HxB]) or not expressing Vpr (WPI). (A and B) GFP⁺ cells were sorted and analyzed for cell cycle profiles by flow cytometry. Proportions of cells in G₁ and G₂ phases were enumerated using the ModFit mathematical model. (A) Representative results from one experiment. (B) Compilation of 3 experiments in which mean G₂/G₁ ratios ± standard deviations (SD) for primary Vprs were expressed as percentages of that obtained for HxB Vpr. (C) CEM cells were also stained with anti-Vpr MAb (8D1) and analyzed by flow cytometry for Vpr expression in GFP⁺ cells. MFI values were obtained after subtraction of signals given by cells stained with a relevant isotype control antibody. Shown are data representative of 3 experiments. (D) HEK293T cells were transfected with lentiviral vectors expressing no Vpr (WPI), Vpr P, or HxB Vpr and assessed for Vpr expression by Western blotting using anti-Vpr pAb.