Endogenous amdoparvovirus-related elements reveal insights into the biology and evolution of vertebrate parvoviruses.

Abstract

Amdoparvoviruses (family Parvoviridae: genus Amdoparvovirus) infect carnivores, and are a major cause of morbidity and mortality in farmed animals. In this study, we systematically screened animal genomes to identify PVe disclosing a high degree of similarity to amdoparvoviruses, and investigated their genomic, phylogenetic and protein structural features. We report the first examples of full-length, amdoparvovirus-derived PVe in the genome of the Transcaucasian mole vole (Ellobius lutescens). Furthermore, we identify four further PVe in mammal and reptile genomes that are intermediate between amdoparvoviruses and their sister genus (Protoparvovirus) in terms of their phylogenetic placement and genomic features. In particular, we identify a genome-length PVe in the genome of a pit viper (Protobothrops mucrosquamatus) that is more like a protoparvovirus than an amdoparvovirus in terms of its phylogenetic placement and the structural features of its capsid protein (as revealed by homology modeling), yet exhibits characteristically amdoparvovirus-like genome features including: (i) a putative middle ORF gene; (ii) a capsid gene that lacks a phospholipase A2 (PLA2) domain; (iii) a genome structure consistent with an amdoparvovirus-like mechanism of capsid gene expression. Our findings indicate that amdoparvovirus host range has extended to rodents in the past, and that parvovirus lineages possessing a mixture of proto- and amdoparvovirus-like characteristics have circulated in the past. In addition, we show that PVe in the mole vole and pit viper encode intact, expressible replicase genes that have potentially been co-opted or exapted in these host species.