关键词: 粘孢子虫, 蛋白酶, 生物信息学分析, 克隆, 表达

Abstract: Myxosporea are the common parasites of fish, which causing serious loss in fish production. The role of Myxosporea proteases and inhibitors in affecting their invasion and infection is increasingly reported. Based on the early transcriptome data of Myxosporea Thelohanellus kitauei, three highly expressed secret protease genes, TK Papain-1, TK Papain-2 and TK Pepsin, were successfully cloned. Using bioinformatics analysis, TK Papain-1 and TK Papain-2 are member of the papain (C1A) family, which encodes cysteine proteases. These two protease genes encoding 150 and 322 amino acids and the protein sizes are 17.06 kDa and 36.7 kDa respectively. TK pepsin encodes aspartic proteases. This gene encodes a total of 491 amino acids and the protein size is 55.41 kDa. All the proteases have signal peptide sequences, which are secret protease; through the construction of phylogenetic trees, we found that the amino acid sequence of those proteases were similar with homologous sequences of Nematostella vectensis, Hydra vulgar and Pseudocohnilembus persalinus. Moreover, using multiple sequence alignment, the conserved sites of those secretors of protease and the protein corresponding to the predicted size was obtained by heterologous expression. This study provided a basis for further research on the Myxosporium protease properties, and infection mechanism.

Key words: Myxosporea, protease, bioinformatics analysis, gene clone, expression