cDNA cloning and expression analysis of a cyclooxygenase-2 from sea bass (Dicentrarchus labrax L.) after vaccination

Two cyclooxygenases (COX) are involved in the biosynthetic pathway of prostaglandin synthesis. COX-1 is constitutively expressed, while COX-2 is induced by various inflammatory signals, including cytokines, growth factors, and lipopolysaccharide (LPS). COX-1 and COX-2 have been isolated from several mammals, birds, and recently from some fish species. In fish, COX activities are involved in inflammatory responses and in the control of reproduction. In the present study, we describe the homology cloning of sea bass (Dicentrarchus labrax L.) COX-2 gene. The full-length COX-2 cDNA consists of 2350 nucleotides that when translated gives a predicted 596-amino acid molecule. The sequence displayed high nucleotide and amino acid identity with other fish COX-2 genes, and this relationship was also evident in a phylogenetic tree generated using peptide data. We also demonstrate that sea bass COX-2 is not constitutively expressed and can be induced by factors such as LPS and recombinant sea bass interleukin-1β. In addition, injection of sea bass with killed Vibrio anguillarum up-regulated the expression of this cyclooxygenase, and therefore, it could be useful as a marker in aquaculture.