Cloning and expression analysis of Serum Amyloid A (SAA) from Exopalaemon carinicauda (Holthuis, 1950) (Caridea, Palaemonidae)

Serum amyloid A (SAA), an acute-phase protein, has been demonstrated to play a critical role in the inflammatory response. However, data regarding its function in crustaceans are still scarce. In the present study, cDNA of SAA from Exopalaemon carinicauda (Holthuis, 1950) (designated as EcSAA) was cloned and characterized. The full-length cDNA was 683 bp, including an open reading frame (ORF) of 267 bp that encoded 88 amino acid residues. The predicted amino acid sequence of EcSAA contained characteristic motifs of the SAA family. The EcSAA was widely expressed in all tissues, with the highest expression in gill and hepatopancreas. In response to the Vibrio anguillarum Bergeman, 1909 challenge, EcSAA mRNA was up-regulated in gill, hepatopancreas, and haemolymph. These results suggest thatEcSAA may be a constitutive and inducible acute-phase protein involved in anti-pathogen responses in E. carinicauda.