Genomic characterization of Felis catus papillomavirus-3: a novel papillomavirus detected in a feline Bowenoid in situ carcinoma.

There is increasing evidence that papillomaviruses (PVs) may cause skin cancer in cats. Neoplasms most frequently contain Felis domesticus PV type 2 (FdPV-2) DNA, but other PV DNA sequences have also been detected suggesting multiple PVs could cause disease. One of these sequences, FdPV-MY2, was previously detected in 5 of a series of 70 feline skin cancers. The aim was to determine the genome sequence of this PV. Using the circular nature of PV DNA, 'outward facing' primers specific for FdPV-MY2 were designed and amplified a 7300 bp length of DNA from a feline Bowenoid in situ carcinoma (BISC) that showed microscopic evidence of a viral etiology and tested positive for FdPV-MY2 DNA. The PCR product was sequenced using next generation sequencing technology. The full genomic sequence of the virus, comprising 7583 bp, was assembled and analyzed. As this is the third PV from a domestic cat, the virus was designated Felis catus PV type 3 (FcaPV-3). Consistent with other PVs, the putative coding regions of FcaPV-3 were predicted to produce 6 early proteins and 2 late ones. Classification was difficult as the virus contained over 60% nucleotide similarity within the ORF L1 with PVs from 3 different genera. However, based on phylogenetic analysis of ORF L1, FcaPV-3 was most closely related to the tau-PVs CPV-2 and CPV-7. As FcaPV-3 has over 60% nucleotide similarity with the ORF L1 of both tau-PVs, it is proposed that FcaPV-3 is classified in the genus Taupapillomavirus and is the first non-canine PV in this genus.