Figure 5. Wild-type, but not mutant, p68 activates expression from the PLK1 promoter. (A) H1299 cells were transfected with the PLK1 promoter-luciferase plasmid together with plasmids expressing wild-type p68 or an ATPase/helicase mutant p68 (NEAD-p68) and assayed for luciferase activity. The results represent the mean ± SD of 3 independent experiments, each performed in triplicate. P values were calculated using Student paired t test, where P < 0.05 is considered to be significant. (B) Western blot showing the level of Myc-tagged p68 expressed in H1299 cells, with actin serving as loading control.