Identification and characterization of a novel papillomavirus in thornback skate (Raja clavata)

Papillomaviruses are non-enveloped, double-stranded DNA viruses capable of infecting a wide range of vertebrates, from chondrichthyans to mammals. In this study, we report for the first time the identification and complete genome of a papillomavirus in the thornback skate (<i>Raja clavata</i>), named <i>Raja clavata</i> papillomavirus 1 (RclaPV1). The genomic sequence was determined using a metagenomic approach and subsequently confirmed by PCR. The RclaPV1 genome is 5,539 bp in length and displays the typical organization of papillomaviruses, encoding 4 core proteins on a single DNA strand: two early genes (E1 and E2) and two late genes (L1 and L2). Maximum likelihood phylogenetic analyses of the L1 and E1 genes indicate that RclaPV1 belongs to the <i>Secondpapillomavirinae</i> subfamily, clustering with fish and amphibian papillomaviruses and showing closer evolutionary relationships to amphibians than to fish.