FIG 11.

The HPV-18 E6 PBM contributes to inhibition of p53's transcriptional transactivation activity in the absence of E6AP. (A) H1299 cells were transfected with the indicated promoter constructs upstream of a luciferase promoter—p21-Luc (A), Mdm2-Luc (B), together with plasmids expressing p53 and either wild-type HPV-18 E6 or mutant HPV-18 E6 delPBM in the presence or absence of E6AP. The histograms show the results from at least three independent experiments quantified using Student's t test; the error bars indicate standard errors of the mean. Also shown are the P values (*, P < 0.05; ns, nonsignificant) for the changes in relative luciferase activity. (C) Corresponding Western blot for the luciferase analysis confirms the knockdown of E6AP from the cells and expression of pE6, total E6, p53, and β-gal.