Characterization and Transcript Expression Analyses of Atlantic Cod .

Viperin is a key antiviral effector in immune responses of vertebrates including the Atlantic cod (). Using cloning, sequencing and gene expression analyses, we characterized the Atlantic cod at the nucleotide and hypothetical amino acid levels, and its regulating factors were investigated. Atlantic cod cDNA is 1,342 bp long, and its predicted protein contains 347 amino acids. Using analyses, we showed that Atlantic cod is composed of 5 exons, as in other vertebrate orthologs. In addition, the radical SAM domain and C-terminal sequences of the predicted Viperin protein are highly conserved among various species. As expected, Atlantic cod Viperin was most closely related to other teleost orthologs. Using computational modeling, we show that the Atlantic cod Viperin forms similar overall protein architecture compared to mammalian Viperins. qPCR revealed that is a weakly expressed transcript during embryonic development of Atlantic cod. In adults, the highest constitutive expression of transcript was found in blood compared with 18 other tissues. Using isolated macrophages and synthetic dsRNA (pIC) stimulation, we tested various immune inhibitors to determine the possible regulating pathways of Atlantic cod . Atlantic cod showed a comparable pIC induction to other well-known antiviral genes (e.g., and ) in response to various immune inhibitors. The pIC induction of Atlantic cod was significantly inhibited with 2-Aminopurine, Chloroquine, SB202190, and Ruxolitinib. Therefore, endosomal-TLR-mediated pIC recognition and signal transducers (i.e., PKR and p38 MAPK) downstream of the TLR-dependent pathway may activate the gene expression response of Atlantic cod . Also, these results suggest that antiviral responses of Atlantic cod may be transcriptionally regulated through the interferon-activated pathway.