Abstract：
Cathepsin C is a cysteine protease widely found in invertebrates and vertebrates, and has the important physiological role participating in proteolysis in vivo and activating various functional proteases in immune/inflammatory cells in the animals. In order to study the role of cathepsin C in the disease resistance of shrimp, we cloned cathepsin C gene (MjcathC) from Marsupenaeus japonicus, analyzed its expression patterns in various tissues, performed MjcathC-knockdown, and finally challenged experimental shrimps with Vibrio alginolyticus and WSSV. The results have shown the full length of MjcathC is 1782 bp, containing an open reading frame of 1350 bp encoding 449 amino acids. Homology analysis revealed that the predicted amino acid sequence of MjcathC shared respectively 88.42 %, 87.36 % and 87.58 % similarity with Penaeus monodon, Fenneropenaeus penicillatus and Litopenaeus vannamei. The expression levels of MjcathC in various tissues of healthy M. japonicus are the highest in the liver, followed by the gills and heart, and the lowest in the stomach. The expression levels of MjcathC were significantly up-regulated in all examined tissues of shrimp challenged with WSSV or V. alginolyticus. After knockdown-MjcathC using RNAi technology in M. japonicus, the expression levels of lectin and heat shock protein 70 in MjcathC-knockdown shrimp were significantly down-regulated, and the mortality of MjcathC-knockdown shrimp challenged by WSSV and V. alginolyticus significantly increased. Knockdown of the MjcathC reduced the resistance of M. japonicus to WSSV and V. alginolyticus. The above results have indicated that cathepsin C may play an important role in the antibacterial and antiviral innate immunity of M. japonicus.
摘要：
组织蛋白酶C是一种半胱氨酸蛋白酶，广泛存在于无脊椎动物和脊椎动物中。并在体内参与蛋白水解并激活动物免疫/炎症细胞中的各种功能性蛋白酶具有重要的生理作用。为了研究组织蛋白酶C在对虾抗病性中的作用,我们从日本浮对虾中克隆了组织蛋白酶C基因（MjcathC），分析了其在各种组织中的表达模式，进行了MjcathC击倒，最后用溶藻弧菌和WSSV挑战实验虾。结果表明，MjcathC的全长为1782bp，包含一个1350bp的开放阅读框，编码449个氨基酸。同源性分析表明，MjcathC的预测氨基酸序列分别共有88.42%，与斑节对虾的相似性分别为87.36%和87.58%,对虾和凡纳滨对虾。MjcathC在健康日本猪瘟的各种组织中的表达水平在肝脏中最高，其次是ill和心脏，和最低的胃。在用WSSV或溶藻弧菌攻击的虾的所有检查组织中，MjcathC的表达水平均显着上调。使用RNAi技术在刺槐中敲除MjcathC后，MjcathC敲低对虾凝集素和热休克蛋白70的表达水平显著下调,受WSSV和溶藻弧菌攻击的MjcathC敲除虾的死亡率显着增加。MjcathC的击倒降低了日本血吸虫对WSSV和溶藻弧菌的抗性。以上结果表明，组织蛋白酶C可能在日本猪瘟的抗菌和抗病毒先天性免疫中起重要作用。
