Characterization of a new C-type lectin from common carp Cyprinus carpio

A new C-type lectin with putative mannose specificity was identified from the expressed sequence tag (EST) analysis of cDNA library from common carp head kidney (HK), stimulated with concanavalin A and lipopolysaccharide (LPS) during a routine EST analysis. The full sequence of 627 bp was identified by 5'-rapid amplification of cDNA ends. The gene is composed of 146 amino acid residues, including an 18-residue signal peptide for secretion and a single carbohydrate-recognition domain of approximately 118 residues typical of C-type lectins. Based on the predicted structure, this is a calcium dependent C-type lectin with putative mannose specificity suggested by the presence of an EPN motif. By hemagglutination assay, the mannose specificity of the Ca-CTL was determined. Reverse transcription (RT) PCR analysis demonstrated the expression of Ca-CTL mRNA in the hematopoietic organs and also the level of expression increased with LPS induction. Localization studies by in situ hybridization showed the presence of transcripts in the organs.