Experimental piscine alphavirus RNA recombination in vivo yields both viable virus and defective viral RNA.
RNA recombination in non-segmented RNA viruses is important for viral evolution and documented for several virus species through in vitro studies. Here we confirm viral RNA recombination in vivo using an alphavirus, the SAV3 subtype of Salmon pancreas disease virus. The virus causes pancreas disease in Atlantic salmon and heavy losses in European salmonid aquaculture. Atlantic salmon were injected with a SAV3 6K-gene deleted cDNA plasmid, encoding a non-viable variant of SAV3, together with a helper cDNA plasmid encoding structural proteins and 6K only. Later, SAV3-specific RNA was detected and recombination of viral RNA was confirmed. Virus was grown from plasmid-injected fish and shown to infect and cause pathology in salmon. Subsequent cloning of PCR products confirming recombination, documented imprecise homologous recombination creating RNA deletion variants in fish injected with cDNA plasmid, corresponding with deletion variants previously found in SAV3 from the field. This is the first experimental documentation of alphavirus RNA recombination in an animal model and provides new insight into the production of defective virus RNA.
Norwegian University of Life Sciences, Faculty of Veterinary Medicine and Biosciences, P.O. Box 8146 Dep., N-0033 Oslo, Norway.
Elin
E
Petterson
Norwegian University of Life Sciences, Faculty of Veterinary Medicine and Biosciences, P.O. Box 8146 Dep., N-0033 Oslo, Norway.
Tz-Chun
TC
Guo
Norwegian University of Life Sciences, Faculty of Veterinary Medicine and Biosciences, P.O. Box 8146 Dep., N-0033 Oslo, Norway.
Øystein
Ø
Evensen
Norwegian University of Life Sciences, Faculty of Veterinary Medicine and Biosciences, P.O. Box 8146 Dep., N-0033 Oslo, Norway.
Aase B
AB
Mikalsen
D000524:Alphavirus / Q000235:genetics*; D000818:Animals; D002460:Cell Line; D003673:Defective Viruses / Q000235:genetics*; D023421:Models, Animal; D017685:Oncorhynchus keta / Q000821:virology*; D010957:Plasmids / Q000008:administration & dosage; D012367:RNA, Viral / Q000235:genetics*; D011995:Recombination, Genetic; D017384:Sequence Deletion
D012367:RNA, Viral