Identification and expression analysis of a fibrinogen alpha chain-like gene in Atlantic salmon (Salmo salar)

Abstract

Fibrinogen is a protein involved in platelet aggregation that is essential for the coagulation of blood, and it plays a role in the fish immune system. In this study, a fibrinogen alpha chain-like gene of the Atlantic salmon (Salmo salar) (designated Ss-FGA) was cloned, and its expression pattern was analyzed after fish were infected by the bacterium Aeromonas salmonicida. The Ss-FGA gene contains a 135 base pair (bp) 5′-untranslated region (UTR), an open reading frame (ORF) of 1512 bp that encodes a 503 amino acid polypeptide, and a 624 bp 3′-UTR. The expression level of Ss-FGA was higher in the liver than in other tissues, indicating that the liver is the major organ for protein synthesis of Ss-FGA. Additionally, expression levels of Ss-FGA differed between treatment and control samples. The results of FISH (Fluorescence in situ hybridization) showed that the expression of Ss-FGA gene in the liver tissue of Atlantic salmon after infected by A. salmonicida. In conclusion, this study revealed that Ss-FGA might play important roles in the innate immune responses to bacterial invasion in Atlantic salmon.

Keywords

• Salmo salar
• Fibrinogen
• Gene expression
• Innate immunity