Short Communication Isolation and genomic characterization of the first Norway rat (Rattus norvegicus) papillomavirus and its phylogenetic position within Pipapillomavirus, primarily infecting rodents

A series of papillomavirus (PV) types have been isolated from different rodent species, and most of them belong to the genus Pipapillomavirus. We isolated and sequenced the complete genome of a novel PV type (designated RnPV) from the oral cavity of the Norway rat (Rattus norvegicus), as well as an L1 gene fragment from hair-follicle cells of the European beaver (Castor fiber). As inferred from amino acid sequence data, RnPV clustered within the b+c+p+j-PV supertaxon as a member of the genus Pipapillomavirus. The closest relatives of RnPV were McPV-2 and MmPV, and time estimates indicated that the genus Pipapillomavirus originated in the late Cenozoic era. The close relationship of RnPV to other murid PV types supports the hypothesis of co-divergence between members of the genus Pipapillomavirus and their hosts. However, the derived Neogene origin of the genus Pipapillomavirus is much younger than has been considered for the Rodentia as the primary hosts, indicating that alternative interpretations of the phylogenetic trees should be conceived. Papillomaviruses (PVs) are a diverse group of small, nonenveloped, double-stranded DNA viruses. Their structurally conserved, circular genome comprises approximately 8000 bp and is organized in up to eight open reading frames (ORFs), including the four major genes E1 and E2 (i.e. early genes) and L2 and L1 (late genes). PVs infect epithelial tissues of humans and different animal species, causing cutaneotropic and mucosotropic proliferative lesions. The presence of genital PV types is the major risk