Differential expression of immune and stress genes in the skin of Atlantic cod (Gadus morhua).

The present study describes the transcriptional profiles of selected immune and stress genes with putative important roles in the cutaneous immune defense of Atlantic cod (Gadus morhua). In addition it shows differential expression of many genes at the dorsal and ventral sides of fish, in general having the highest expression at the latter side. Genes related to antibacterial activity, antiviral response, cytokine production, glucose transport, stress response and anti-apoptotic activity were monitored and bactericidal/permeability-increasing protein/lipopolysaccharide-binding protein (BPI-LBP), g-type lysozyme, transferrin, metallothionein, fortilin, interferon regulatory factor-1 (IRF-1), a CC chemokine isoform, interleukin-8 (IL-8), glucose transport (GLUT)-1, -3 and -4, Cu,Zn-superoxide dismutase (Cu,Zn-SOD), catalase and hsp 70 showed significantly higher expression at the ventral side. Further g-type lysozyme, metallothionein, fortilin, IRF-1, interferon γ, interleukin-1β (IL-1β), GLUT-3 and -4, catalase and anti apoptotic gene Bcl-X1 were highly expressed in adult cod skin. Therefore fish skin can be considered an immunological active site, especially at the ventral side of Atlantic cod.