cDNA CLONING AND EXPRESSION ANALYSIS OF HEMOCYANIN SUBUNIT GENE IN EXOPALAEMON CARINICAUDA

This study cloned the cDNA of hemocyanin subunit from Exopalaemon carinicauda (named EcHcL) by rapid amplification of cDNA ends (RACE). The EcHcL cDNA was 2192 bp in length including a 2034 bp open reading frame (ORF) that encoded a 667 amino acids polypeptide with a signal peptide sequence (1—21 amino acid residues). The predicted molecular weight of the mature peptide was 78.5 kD. The homology analysis revealed that the amino acid sequence of EcHcL was highly conserved with other arthropod. The homology similarities of EcHcL amino acids with Macrobarchium nipponense hemocyanin and Litopenaeus vannamei amino acid sequence were 87% and 73%, respectively. The similarity of the M domain of the amino acid sequence between EcHcL and other shrimp was about 90%. EcHcL was detected in all tested tissues including gill, ovary, hepatopancreas, heart, intestine, muscle, stomach, abdominal ganglion, eyestalk and haemocytes with the highest expression in hepatopancreas. EcHcL was induced distinctly in the hepatopancreas and haemocytes of shrimp by Staphylococcus aureus, Vibrio parahaemolyticus and white spot syndrome virus (WSSV). The results suggest that the different temporal expression pattern of EcHcL might play an important role in shrimp immune system.