Molecular cloning and mRNA expression of cathepsin C in white shrimp,Litopenaeus vannamei

The cDNA encoding cathepsin C from the haemocytes of Litopenaeus vannamei (designated LVcathepsinC) was cloned by rapid amplification of cDNA ends (RACE) techniques. The full length of LVcathepsinC cDNA was 2026 bp, with an open reading frame of 1356 bp, which encoded a polypepetide of 451 amino acid residues with a theoretical molecular weight of 50.76 kDa and an estimated isoelectric point of 6.01. LVcathepsinC showed high similarity to other organisms on performing blast analysis. Fluorescent quantitative real‐time reverse transcriptase‐polymerase chain reaction was used to examine the expression of the LVcathepsinC gene in haemocytes of L. vannamei after the challenge of bacteria Vibrio alginolyticus. There was a clear time‐dependent expression pattern of LVcathepsinC after the bacterial challenge, and the mRNA expression reached a maximum level at 4 h post challenge, and then returned to the control level after 8 h. The up‐regulated mRNA expression of LVcathepsinC in L. vannamei after bacterial challenge indicates that the LVcathepsinC gene is inducible and may be involved in immune response.