Complete genomes and phylogenetic positions of bovine papillomavirus type 8 and a variant type from a European bison

Abstract

The DNA of bovine papillomavirus (BPV) type 8 was extracted from papillomas on cattle kept in Japan, and DNA of bovine papillomavirus BPV-8-EB was extracted from a European bison (Bison bonasus) born in Italy and released into the wild in Slovakia. The DNA genomes of these BPVs were amplified using multiply primed rolling circle amplification and polymerase chain reaction, then characterized by direct sequencing method. The BPV-8 and BPV-8-EB genomes consisted of 7,791 base pairs (bp) and 7,773 bp, respectively (GenBank accession numbers DQ098913 and DQ098917). The nucleotide sequence similarity of these BPVs indicated that BPV-8-EB was a variant of BPV-8. In the genome of BPV-8-EB, one nucleotide substitution was found in the E2 and E5 open reading frame (ORF) and upstream regulatory region (URR), and a short deletion and addition were found in the URR. The high similarity of sequences between the BPV-8 to BPV-5 in total genome (70%) and L1 ORF (75%) as well as a phylogenetic analysis were the bases for classifying BPV-8 in the genus Epsilon papillomavirus. The BPV-8 E6 and E7 ORFs/proteins also showed some characteristic features of genus Epsilon papillomavirus. However, BPV-8 contained E4 ORF, which was not found in BPV-5. In addition, the secondary structure of E5 proteins of BPV-5 and BPV-8 suggested that these proteins may have cell-transforming ability.