AZT-mediated reactivation of p53 functions and stabilization of CDKI p21^WAF and p27^KIP. (A) Expression of p21waf and Bax mRNA before and after ionizing radiation in AZT-treated MT-2 cells (18 weeks). GAPDH was used as internal control for amplification. (B) Western blot analysis for expression of p21^WAF and p27^KIP in untreated MT-2 or after culture with AZT for 18 weeks. Equal amounts (50 μg) of each extract were used and confirmed by β-tubulin. (C) Analysis of p21^WAF and p27^KIP mRNA expression by RT-PCR in MT-2 and after culture with AZT for 18 weeks. GAPDH was used as internal control for amplification. (D) Western blot analysis for expression of p27^KIP in untreated MT-2 or after culture with AZT for 18 weeks, in absence or presence of proteosome inhibitor lactacystin. Equal amounts of each extract (50 μg) were used and confirmed by β-tubulin. (E) MT-2–derived p53 cDNA nucleotide sequence. (F) p53 amino acid sequence from MT-2 cells compared with wild-type p53. (G) RT-PCR for p53 responsive genes before and after gamma irradiation of MT2 cells.