Transcription of the tyrosinase gene family in an Atlantic salmon leukocyte cell line (SHK-1) is influenced by temperature, but not by virus infection or bacterin stimulation

• Elevated temperature induces up-regulation of the tyrosinase gene family.
• Virus infection has no effect on the regulation of the tyrosinase gene family.
• Temperature does not affect the transcription of MHC class II or IFN-1 in vitro.

The present study was performed to address putative links between the immune and pigmentary systems. A pigment-producing leukocyte-like cell-line (SHK-1 cells) of Atlantic salmon (Salmo salar L.) was exposed to different temperatures, poly I:C, bacterin or infected with virus (infectious pancreatic necrosis virus or infectious salmon anaemia virus). The effect of this stimulation regarding the transcription-pattern of the tyrosinase gene family (melanin genes) and the immune-related genes MHC class II and IFN-1 was analysed using real-time RT-qPCR. At 10 °C cultivation, tyrosinase and dopachrome tautomerase remained unregulated. At 15 °C, a moderate up-regulation was induced, while at 20 °C, these genes were up-regulated in an exponential manner over time. Temperature did not affect the transcription of the immune-related genes. Virus infections, poly I:C or bacterin had no influence on the transcription of the melanogenesis-related genes, but triggered the immune-related genes. Our findings revealed no connections between the pigmentary and immune systems, but demonstrated a hereto undiscovered temperature-effect on the tyrosinase gene family.