CHARACTERIZATION OF HUMAN PAPILLOMAVIRUS TYPE 57B - TRANSFORMING ACTIVITY AND COMPARATIVE SEQUENCE-ANALYSIS AS PROBES FOR BIOLOGICAL DETERMINANTS ASSOCIATED WITH HIGH-RISK ONCOGENIC VIRUSES

The association of human papillomavirus type 57 (HPV-57) with premalig nant and malignant tumors of the nasal cavity was previously reported (Wu et al., Lancet 341, 522, 1993). We determined the complete nucleot ide sequence of HPV-57b (GenBank 37537), which was molecularly cloned from a benign fungiform papilloma, and compared it with other HPV type s and HPV-57a, which was cloned from an inverted papilloma of the maxi llary sinus by de Villiers et al. (Virology 171, 248. 1989). Comparati ve and phylogenetic analysis of amino acid sequences of the HPV-57b on cogenes E5, E6, and E7 were performed with HPV-6, 11, 16, and 18. Phyl ogenetic trees using the Jotun-Hein algorithm indicated a closer relat ionship of HPV-57b E5 and E7 with corresponding genes of HPV-18. Signa ture pattern analysis of these two oncogenes was also in agreement wit h a closer relatedness to HPV-16 and 18 oncogenes, which are associate d with a high risk for malignant progression. Compared with 7861 bp of HPV-57a, HPV-57b had 7868 bp as well as differences in the restrictio n enzyme sites and the open reading frames, including at least five ad ditional ones. To investigate the oncogenic potential of HPV-57b, NIH 3T3 and REF52 cells were cotransfected with two plasmids: pKP54.HPV-57 b, which contains the HPV-57b genome, and pMT.neo.1, which confers res istance to G418. After selection in culture medium containing G418, 58 % of the G418(r) NIH 3T3 colonies and 47% of the G418(r) REF52 colonie s exhibited morphological transformation. These results indicate that the transcriptional regulatory elements and the oncoproteins of HPV-57 b are active in vitro to induce cellular transformation, as are other high-risk HPV types.