FIG. 4.

Virion-associated Vpr causes ΔΨm dissipation. (A) Jurkat cells were mock infected or infected with Vpr(+)^trans or Vpr(−) viruses at an MOI of 0.5. Fifty hours postinfection, the ΔΨm was measured by using the MitoProbe DiIC₁(5) assay kit. Infected cells (0.4 × 10⁶) were labeled with 50 nM DiIC₁(5) at 37°C in the dark for 30 min before analyses by flow cytometry to generate dot plots. The fluorescence intensities of EGFP and DilC₁(5) are represented on the x axis and y axis, respectively. Uninfected cells treated with 250 μM of carbonyl cyanide m-chlorophenyl hydrazone before being labeled with DiIC₁(5) were used as a positive control. NLEGFP virus infection and subsequent staining with DiIC₁(5) were used as a reference. The plots shown are representative of one of four experiments. (B) The ratio of the percentage of EGFP⁺ ΔΨm_high to that of EGFP⁺ ΔΨm_low cells was determined for each viral infection from the dot plots and was plotted on a bar graph. The results are shown as means plus standard deviations. Note that the ratio indicated for mock infection is the ratio of the percentage of ΔΨm_high cells to that of ΔΨm_low cells.