FIG. 2.

Augmentation of IE1-induced apoptosis by PE38. (A) Cells were transfected with plasmids expressing pe38, a FLAG-tagged version of pe38, and orf154, or they were cotransfected with a plasmid expressing an epitope-tagged version of ie-1 and plasmids expressing cat, pe38, FLAG-pe38, orf154, or a combination of pe38 and orf154. All genes were under hsp70 promoter control. At 12 h after induction of gene expression by heat shock, the cells were stained with trypan blue to determine viability. Cells transfected with pHSP70CATPLVI⁺, a plasmid expressing the cat gene, served as a negative control of apoptotic activity (percentage of apoptosis). The results represent averages of at least three independent experiments, and standard errors are indicated. (B) Cells were transfected with plasmids expressing the hsp70-promoted genes indicated above each lane. At 18 h posttransfection, gene expression was induced by heat shock. Three hours after heat shock, cells were harvested and oligonucleosomal degradation analysis was performed as described previously (7). DNA molecular markers (sizes in kilobase pairs) are indicated at right.