Based on the EST sequence from a hemocyte cDNA library, the cathepsin L cDNA of
Exopalaemon
carinicauda
(
EcCatL) was cloned by rapid amplification of cDNA ends (RACE). The
EcCatL cDNA was 1136 bp in length, which contains
an open reading frame (ORF) of 960 bp, encoding a 319 amino-acid polypeptide. Homology analysis revealed that the amino
acid sequence of
EcCatL was highly conserved with its homologs in other crustaceans. The similarities of EcCatL with the
CatL of
Palaemonetes varians
and
Pandalus borealis
were 92% and 76%, respectively. Phylogenetic analysis showed that
EcCatL was in the same branch as that of
Palaemonetes varians. The expression levels of
EcCatL in different tissues were
analyzed by quantitative real-time PCR. Expression of
EcCatL was detected in all tested tissues of
E. carinicauda, including
hemocytes, gill, hepatopancreas, muscle, ovary, intestine, stomach and eyestalk, with the highest expression level in
hepatopancreas. After challenged with
Vibrio anguillarum
or white spot syndrome virus, the expression of
EcCatL were
up-regulated in the hemocytes and hepatopancreas of
E. carinicauda. Our results implied that
EcCatL might play an important
role in the prawn immune response.
