FIG. 4.

Uncoupling of Zta-mediated p21 and p27 induction from p53 induction. (A and B) Zta-mediated induction of p27 and p21 in p53-suppressed HeLa cells. Cells were nontransfected (non-transf.) or transfected with 5 μg of the indicated pMARK expression vector and 25 μg of either a control vector (RSV) or a HPV E6 expression vector (RSV-E6). Cells were analyzed as indicated in the legend to Fig. 3. wt, wild type. (C) A stable inducible SAOS2-Zta cell line was generated, and the induction experiment was carried out as described for Fig. 1. Cells were harvested at the indicated times following tetracycline withdrawal, and extracts were subjected to Western blot analysis using anti-Zta (M47) and anti-p21 (C19G; Santa Cruz) antibodies.