Characterization of Frog Virus 3 knockout mutants lacking putative virulence genes.
To identify ranavirus virulence genes, we engineered Frog Virus 3 (FV3) knockout (KO) mutants defective for a putative viral caspase activation and recruitment domain-containing (CARD) protein (Δ64R-FV3) and a β-hydroxysteroid dehydrogenase homolog (Δ52L-FV3). Compared to wild type (WT) FV3, infection of Xenopus tadpoles with Δ64R- or Δ52L-FV3 resulted in significantly lower levels of mortality and viral replication. We further characterized these and two earlier KO mutants lacking the immediate-early18kDa protein (FV3-Δ18K) or the truncated viral homolog of eIF-2α (FV3-ΔvIF-2α). All KO mutants replicated as well as WT-FV3 in non-amphibian cell lines, whereas in Xenopus A6 kidney cells replication of ΔvCARD-, ΔvβHSD- and ΔvIF-2α-FV3 was markedly reduced. Furthermore, Δ64R- and ΔvIF-2α-FV3 were more sensitive to interferon than WT and Δ18-FV3. Notably, Δ64R-, Δ18K- and ΔvIF-2α- but not Δ52L-FV3 triggered more apoptosis than WT FV3. These data suggest that vCARD (64R) and vβ-HSD (52L) genes contribute to viral pathogenesis.
Department of Microbiology & Immunology, University of Rochester Medical Center Rochester, NY 14642, United States.
Francisco De Jesús
Fde J
Andino
Department of Microbiology & Immunology, University of Rochester Medical Center Rochester, NY 14642, United States.
Leon
L
Grayfer
Department of Microbiology & Immunology, University of Rochester Medical Center Rochester, NY 14642, United States.
Guangchun
G
Chen
Department of Microbiology, University of Mississippi Medical Center, Jackson, MS 39216, United States.
V Gregory
VG
Chinchar
Department of Microbiology & Immunology, University of Rochester Medical Center Rochester, NY 14642, United States.
Eva-Stina
ES
Edholm
Department of Microbiology & Immunology, University of Rochester Medical Center Rochester, NY 14642, United States. Electronic address: jacques_robert@urmc.rochester.edu.
Jacques
J
Robert
D029845:Amphibian Proteins / Q000172:deficiency / Q000235:genetics*; D000818:Animals; D053468:CARD Signaling Adaptor Proteins / Q000172:deficiency / Q000235:genetics; D004266:DNA Virus Infections / Q000401:mortality / Q000473:pathology / Q000821:virology*; D015852:Eukaryotic Initiation Factor-2 / Q000235:genetics / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D055786:Gene Knockout Techniques; D054884:Host-Pathogen Interactions; D006913:Hydroxysteroid Dehydrogenases / Q000172:deficiency / Q000235:genetics; D007814:Larva / Q000821:virology; D009154:Mutation; D017995:Ranavirus / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D015398:Signal Transduction; D016019:Survival Analysis; D014774:Virulence; D014779:Virus Replication; D014982:Xenopus laevis / Q000821:virology
D029845:Amphibian Proteins; D053468:CARD Signaling Adaptor Proteins; D015852:Eukaryotic Initiation Factor-2; D006913:Hydroxysteroid Dehydrogenases
Amphibians; Interferon response; Ranavirus; Virulence gene; Xenopus