Different arrangement of human papillomavirus E2 binding sites distinguishes cutaneous types from those associated with mucosal lesions

Abstract

High-risk-type human papillomavirus DNA sequences are found in a high percentage of carcinomas from the uterine-cervix, with the viral E1-E2 gene region usually disrupted and the E6 and E7 oncoproteins consistently expressed. The E2 protein is known to repress early transcription from genital HPV promoters having a proximal E2 binding site (E2BS) close to the TATA box. On the contrary, the E2 protein activates cutaneous early promoters having a longer distance between these sites. Using an in vivo approach we analyzed the regulation, by the BPV-1E2 protein, of a natural HPV-18 promoter where proximal E2BS were placed at variable positions relative to the TATA box, and of heterologous promoters where E2BS was placed upstream of any other known DNA-binding elements. Our results confirm that the E2 protein represses or activates HPV early gene transcription depending on the distance between the TATA box and the proximal E2BS.