p53-Dependent and -independent transactivation by the E6 protein of human papillomavirus type 16

The mechanism by which the E6 protein of human papillomavirus type 16 (HPV-16) transactivates heterologous virus promoters has not been established. In this study, the involvement of p53-mediated transcriptional repression in transactivation by the HPV-16 E6 protein was examined using several virus promoters. HPV-16 E6 transactivated the TATA box-containing simian virus 40 early promoter and the Rous sarcoma virus long terminal repeat in p53-containing cells but not in p53-deficient cells. In contrast, the adenovirus E2 promoter was transactivated both in p53-containing and p53-deficient cells. These results indicate that the transactivation activity of the HPV-16 E6 protein is mediated by p53-dependent and promoter-specific p53-independent pathways.