Unique genome organization of non-mammalian papillomaviruses provides insights into the evolution of viral early proteins

• Published in: Virus Evolution
• Main Authors: Van Doorslaer, Koenraad, Ruoppolo, Valeria, Schmidt, Annie, Lescroël, Amelie, Jongsomjit, Dennis, Elrod, Megan, Kraberger, Simona, Stainton, Daisy, Dugger, Katie M, Ballard, Grant, Ainley, David G, Varsani, Arvind
• Other Authors: Univ Arizona, ACBS & Bio5
• Format: Article in Journal/Newspaper
• Language: English
• Published: OXFORD UNIV PRESS 2017
• Subjects: papillomavirus; evolution; bird; reptile; avian; Cape Crozier; Crozier; Fulmar; Ross Island; Adelie penguin; Antarc*; Antarctica; Fulmarus glacialis; Northern Fulmar; Pygoscelis adeliae
• Online Access: http://hdl.handle.net/10150/627073; https://doi.org/10.1093/ve/vex027

The family Papillomaviridae contains more than 320 papillomavirus types, with most having been identified as infecting skin and mucosal epithelium in mammalian hosts. To date, only nine non-mammalian papillomaviruses have been described from birds (n = 5), a fish (n = 1), a snake (n = 1), and turtles (n = 2). The identification of papillomaviruses in sauropsids and a sparid fish suggests that early ancestors of papillomaviruses were already infecting the earliest Euteleostomi. The Euteleostomi clade includes more than 90 per cent of the living vertebrate species, and progeny virus could have been passed on to all members of this clade, inhabiting virtually every habitat on the planet. As part of this study, we isolated a novel papillomavirus from a 16-year-old female Adelie penguin (Pygoscelis adeliae) from Cape Crozier, Ross Island (Antarctica). The new papillomavirus shares similar to 64 per cent genome-wide identity to a previously described Adelie penguin papillomavirus. Phylogenetic analyses show that the non-mammalian viruses (expect the python, Morelia spilota, associated papillomavirus) cluster near the base of the papillomavirus evolutionary tree. A papillomavirus isolated from an avian host (Northern fulmar; Fulmarus glacialis), like the two turtle papillomaviruses, lacks a putative E9 protein that is found in all other avian papillomaviruses. Furthermore, the Northern fulmar papillomavirus has an E7 more similar to the mammalian viruses than the other avian papillomaviruses. Typical E6 proteins of mammalian papillomaviruses have two Zinc finger motifs, whereas the sauropsid papillomaviruses only have one such motif. Furthermore, this motif is absent in the fish papillomavirus. Thus, it is highly likely that the most recent common ancestor of the mammalian and sauropsid papillomaviruses had a single motif E6. It appears that a motif duplication resulted in mammalian papillomaviruses having a double Zinc finger motif in E6. We estimated the divergence time between Northern fulmar-associated papillomavirus and the other Sauropsid papillomaviruses be to around 250 million years ago, during the Paleozoic-Mesozoic transition and our analysis dates the root of the papillomavirus tree between 400 and 600 million years ago. Our analysis shows evidence for niche adaptation and that these non-mammalian viruses have highly divergent E6 and E7 proteins, providing insights into the evolution of the early viral (onco-)proteins. US National Science Foundation (NSF) [ANT-0944411]; State of Arizona Improving Health TRIF; National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch NC229; Center of Evolution and Medicine Venture Fund (Center of Evolution and Medicine, Arizona State University, USA) grant Open Access Journal. This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [e-mail].