Figure 7.

p53 is a downstream effector of Qp repression. (A) Qp-CAT was down-regulated by coexpression of p53. Qp-CAT was cotransfected into HeLa cells with either wild-type (Wt) or mutant (G245 m, R248 m) p53. p53-CAT formed a positive control for p53 function. The results shown are an average of two experiments, with the standard deviation indicated. (B) Zta is an ineffective repressor of Qp-CAT in p53⁻ cells. The effect of cotransfection of Zta or p53 on Qp-CAT activity was compared in transfected HeLa and p53⁻ Hep3B cells. Qp-CAT activity in the absence of cotransfected Zta and p53 is set at 100%.