Cloning of Interferon in Sea Bream (Sparus aurata): An Important Marker for Immune Response after Viral Infection

The interferons (IFNs) are soluble cytokines involved in the immune response against viral pathogens. In mammals, three families of IFNs have been identified (types I, II and III) and, recently, homologues of type I have been found in different fish species. In this paper we report the cloning of IFN genes from sea bream (Sparus aurata), expression analysis and gene structure. The sea bream IFN cDNA consists of 914 bp that translate in one reading frame to give the entire molecule containing 186 amino acids. The analysis of the sequences revealed the presence of a putative 20 amino acid signal peptide, two cysteine residues and two potential N-glycosylation sites and, finally, a high percentage of identity with type I IFN from mammals compared to type III IFN. Real time PCR was performed after poly I:C stimulation of head kidney leukocytes from sea bream to investigate the expression of sea bream IFN and Mx and an induction was observed for both genes at different time points and with different intensities. The sea bream IFN genes contains four introns, as type III IFN from mammals. The presented results will give the opportunity to investigate more in detail antiviral immune responses, vaccination and immunostimulation effects in sea bream, an economical important species for the South Mediterranean aquaculture. _____________________________________________________________________________________________________________