FIG. 6.

Survival of CV-1 and neuro-2A cells after transfection with LR gene mutants. CV-1 and neuro-2A cells were transfected with pCMV-β-gal (2 μg) and the designated plasmid (4 μg). After transfection, cells were treated with 15 μM C₆-ceramide (CV-1) or etoposide (neuro-2A) for 48 h, fixed, and stained for β-Gal expression. The number of blue cells was counted in exactly the same areas of each well. The number of blue cells that survived treatment was divided by the number of blue cells in each respective nontreated control culture to yield percent cell survival. The data shown are the mean differences as determined by normalizing to pCDNA3.1 alone control as described for Fig. 2. P values for CV-1 cells transfected with the indicated plasmids and treated with C₆-ceramide were as follows: LRT^wt, 0.0020; LRTstop, 0.0680; LRTΔSmaI, 0.0010; and LRTΔHX, 0.00015. P values for transfected neuro-2A cells treated with etoposide were as follows: LRT^wt, 0.0110; LRTstop, 0.524; LRTΔSmaI, 0.801; and LRTΔHX, 0.003.