Sequence analysis and characterisation of virally induced viperin in the saltwater crocodile (Crocodylus porosus)

•C. porosus viperin is the shortest viperin species cloned to date at 338 amino acids.•C. porosus viperin localises to lipid droplets, most likely via its N-terminal amphipathic helix.•C. porosus cells maintain the ability to respond to both dsRNA, dsDNA and infectious ssRNA +ve and –ve sense viruses.•Dengue viral infection of mammalian cells is significantly restricted by C. porosus viperin. A number of pathogens have been detected in crocodiles, however little is known about their ability to control these pathogens. The interferon stimulated gene (ISG), viperin, has gained attention recently as an important host protein involved in multiple arms of the immune response. Viperin in concert with a number of other ISGs was upregulated in response to viral nucleic acid mimics and sendai virus in the C. porosus cell line, LV-1, indicating an intact early innate response to viral infection in these animals for the first time. Viperin was cloned from the LV-1 cell line and shown to have similar localisation patterns as human viperin, as well as demonstrating extremely high conservation with the human orthologue, excepting at the N-terminus. Interestingly, C. porosus viperin was also able to inhibit Dengue virus replication in vitro, showing a high level of intact functionality for this protein across divergent animal species, and perhaps demonstrating its importance in the early innate response to pathogens in the animal kingdom.