Molecular characteristics of cutaneous papillomavirus from the canine pigmented epidermal nevus

To investigate the relation between the canine pigmented epidermal nevus (PEN) and cutaneous papillomavirus, we cloned and sequenced the L1 gene of papillomavirus from the canine pigmented epidermal nevus (PEN). Amplification of DNA sample with the L1 consensus primers yielded an expected fragment of approximately 450-bp. The nucleotide sequences of the fragment showed about 64% of sequence similarity to the L1 region of human papillomavirus isolate CP6108 and less than 57% sequence similarity to those of canine oral papillomavirus (COPV). In situ hybridization determined the presence of papillomavirus DNA mainly in the upper stratum granulosum of skin in this case. The results indicated that the canine cutaneous papillomavirus from the PEN lesion was genetically close to human papillomavirus rather than COPV.