Promoters of type I interferon genes from Atlantic salmon contain two main regulatory regions

• Published in: FEBS Journal
• Main Authors: Bergan, Veronica, Steinsvik, Silje, Xu, Hao, Kileng, Øyvind, Robertsen, Børre
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2006
• Subjects: Atlantic salmon
• Online Access: http://dx.doi.org/10.1111/j.1742-4658.2006.05382.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1742-4658.2006.05382.x; https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1742-4658.2006.05382.x

Recognition of viral nucleic acids by vertebrate host cells results in the synthesis and secretion of type I interferons (IFN‐α/β), which induce an antiviral state in neighboring cells. We have cloned the genes and promoters of two type I IFNs from Atlantic salmon. Both genes have the potential to encode IFN transcripts with either a short or a long 5′‐untranslated region, apparently controlled by two distinct promoter regions, PR‐I and PR‐II, respectively. PR‐I is located within 116 nucleotides upstream of the short transcript and contains a TATA‐box, two interferon regulatory factor (IRF)‐binding motifs, and a putative nuclear factor kappa B (NFκB)‐binding motif. PR‐II is located 469–677 nucleotides upstream of the short transcript and contains three or four IRF‐binding motifs and a putative ATF‐2/c‐Jun element. Complete and truncated versions of the promoters were cloned in front of a luciferase reporter gene and analyzed for promoter activity in salmonid cells. Constructs containing PR‐I were highly induced after treatment with the dsRNA poly(I:C), and promoter activity appeared to be dependent on NFκB. In contrast, constructs containing exclusively PR‐II showed poor poly(I:C)‐inducible activity. PR‐I is thus the main control region for IFN‐α/β synthesis in salmon. Two pathogenic RNA viruses, infectious pancreatic necrosis virus and infectious salmon anemia virus, were tested for their ability to stimulate the minimal PR‐I, but only the latter was able to induce promoter activity. The established IFN promoter‐luciferase assay will be useful in studies of host–virus interactions in Atlantic salmon, as many viruses are known to encode proteins that prevent IFN synthesis by inhibition of promoter activation.