Cloning and characterization of a trypsin-like serine protease gene, a novel regeneration-related gene from Apostichopus japonicus.

Trypsin-like serine protease (TLS) plays an important role in many physiological processes including wound healing, phlogosis reaction, blood clotting, regeneration etc. In this paper, a 1216 bp full-length cDNA sequence of TLS including 39 bp 5' UTR and 355 bp 3'UTR coding for a theoretical 273 amino acids protein was cloned from Apostichopus japonicus by means of the RACE technique for the first time. Bioinformatic analysis revealed that the gene with a 20 residues N-terminal signal peptide and a conserved C-terminal domain belongs to the trypsin-like serine protease superfamily. His78, Asp130 and Ser223 are the principal residues of the catalytic center. In-situ hybridization (ISH) analysis revealed that the TLS gene was widely distributed in different tissues. The expression patterns during different regeneration stages of the TLS gene in the body wall, intestine and respiratory trees were investigated using real-time quantitative PCR. The results show that there was a remarkable and temporary up-regulation of TLS gene expression in the body wall within 1h and subsequent down-regulation of TLS similar to intestine and respiratory trees. With the recovery of tissues, the expression level of the TLS gene was gradually up-regulated and finally reached normal levels. TLS was regulated during different regeneration stages suggesting that TLS is important in the regeneration process of A. japonicus.