Genetic relationship among human papillomaviruses associated with benign and malignant tumours of patients with epidermodysplasia verruciformis.

Human papillomaviruses (HPVs) 5, 8, 19 and 25 induce macular skin lesions in patients with epidermodysplasia verruciformis. HPVs 5 and 8 are known to prevail in skin carcinomas, which develop in about one-third of these patients. We compared the viral DNAs by heteroduplex analysis and on the basis of partial nucleotide sequences. The colinear genomes were closely related and showed nucleotide sequence homology in the range of 40% to 90%. Homology values between 70% and 80% were observed throughout roughly 4 kb of the heteroduplex molecules as estimated after 'calibration' by partial sequencing. Heteroduplex analysis did not support the hypothesis that the different HPV types arise by recombination and allowed no grouping to correlate with the association with malignant tumours. The upstream regulatory sequences of HPVs 8, 19 and 25 appeared highly conserved but differed from those of previously sequenced papillomaviruses in length, in the TATA motif, in the copy numbers and positions of the ACCGN4CGGT palindrome and of a YGCCAA direct repeat, and in two strictly conserved blocks of 33 and 29 nucleotides.