Papillomaviruses are a group of small, nonenveloped, double-stranded DNA viruses that are epitheliotropic. An approximately 8,000-nucleotide circular genome of these viruses encodes 7 to 9 open reading frames, depending on the genotype. Papillomaviruses express 3 regulatory proteins (E1, E2, and E4), 3 oncogenic proteins (E5, E6, and E7), and 2 viral capsid proteins (L1 and L2). The L1 protein is highly conserved, and papillomavirus classification is generally based on sequence analysis of the amino acids of this major capsid protein.1
These epitheliotropic viruses infect a wide range of birds and mammals, including humans,2 and cause benign cutaneous and mucosal epithelial proliferations called papillomas (warts). Occasionally, some papillomaviruses can cause malignant epithelial lesions (carcinomas). Environmental factors, host genetic factors, or both may play a role in the progression of papillomavirus-associated malignancy3,4
Typically, papillomaviruses are host and tissue specific, but there are some exceptions. Equine and feline sarcoids have been associated with bovine papillomavirus.5,6 In 2 recent studies7,8 in cats, HPV type 9 DNA was extracted from a cutaneous papilloma, and the DNA from a papillomavirus present in an SCC of the oral cavity had 92% nucleotide sequence similarity with HPV type 76 DNA. However, those investigators analyzed approximately 25%7 and 30%8 of the L1 gene; thus, the extent to which the HPVs could be genotyped was somewhat limited. Nonetheless, the host species fidelity of papillomaviruses appears not to be absolute, especially in humans and felids. The purpose of the study reported here was to characterize the L1 gene of papillomaviruses detected in epithelial lesions of cats and to determine the relationship between those L1 gene nucleotide sequences and known L1 gene nucleotide sequences of human and feline papillomaviruses.
Felis domesticus papillomavirus type 1
Felis domesticus papillomavirus type 2
Squamous cell carcinoma
Department of Pathology, College of Veterinary Medicine, University of Tennessee, Knoxville, Tenn.
QIAquick kit, Qiagen, Valencia, Calif
Ex Taq premix, TakaRa Bio Inc, Otsu, Shiga, Japan.
Eppendorf Mastercycler gradient, Perkin Elmer Inc, Norwalk. Calif.
ExoSAP-IT, USB, Cleveland, Ohio.
Molecular Biology Resource Facility College of Arts and Sciences, University of Tennessee, Knoxville, Tenn.
ABI prism dye terminator cycle sequencing reaction kit, Perkin Elmer Inc, Foster City Calif
ABI 373 DNA, Perkin Elmer Inc, Foster City Calif
BLAST, National Center for Biotechnology Information, National Institutes of Health, Bethesda, Md. Available at: blast.ncbi.nlm.nih.gov/. Accessed Aug 12, 2009.
Lasergene, DNASTAR Inc, Madison, Wis.
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