Bax is required for the antiapoptotic activity of LMP-1. (A-B) HEK 293-T cells were cotransfected with pGFP, with control-siRNA (A) or Bax-siRNA (B), and with mutant (top row) or wild-type (bottom row) LMP-1 and subsequently incubated with (right column) or without (left column) 1 μM streptonigrin. After staining with Dead Red, cells were gated for pGFP expression by FACS analysis (horizontal axis), and the fraction of Dead Red-stained cells (vertical axis) within the transfected cells was determined. (C) Mean values and 95% confidence intervals (CI₉₅) of 3 experiments as in panels A-B; ^*P < .05. □ indicates control-si; ▦, Bax-si. (D-E) Akata (D) and DG-75 (E) cells were transfected with mutant (top row) or wild-type (bottom row) LMP-1 and subsequently incubated with (right column) or without (left column) 0.25 μM (Akata) or 1 μM (DG-75) streptonigrin. After staining with FITC/anti-PARP and PE/anti-LMP-1, the expression of PARP (horizontal axis) within the fraction of LMP-1-positive cells (vertical axis) was assayed. (F) Mean values and CI₉₅ intervals of 3 experiments as in panels D-E. ^*P < .05; ^**P < .001; n. s. indicates not significant. □ indicates Akata; ▦, DG-75. (A-B, D-E) Numbers show the fractions of apoptotic cells within the gate of transfected cells in the experiment shown; numbers in parentheses refer to the mean of 3 experiments.