Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China.
Fish Shellfish Immunol. 2013 Oct;35(4):1155-62. doi: 10.1016/j.fsi.2013.07.025. Epub 2013 Jul 21.
Serine proteinases (SPs) or SP homologs (SPHs) including clip domain SPs (cSPs) or SPHs (cSPHs) play critical roles in digestion, embryonic development, hemolymph coagulation, and melanization. In this study, one cSP (EscSP) and one SPH, similar to Drosophila masquerade (EsMas), were identified from hepatopancreas of the Chinese mittern crab Eriocheir sinensis. They both possess the clip domains at the N-terminal, EscSP has only one clip domain, but EsMas has seven clip domains. One SP or SP-like domain was at the C-terminal of EscSP and EsMas respectively. In contrast to EscSP, absence of a catalytic residue of Ser resulted in the loss of SP activity of EsMas. Tissue distribution analysis showed that EscSP mRNA was mainly expressed in hepatopancreas, nerve and eyestalk tissue; whereas the EsMas transcript was mainly distributed in eyestalk, muscle, nerve and hemocytes. EscSP in hemocytes showed significant increase after a lipopolysaccharide (LPS) or peptidoglycan (PGN) challenge. However, down-regulation of EsMas was observed in hemocytes challenged by LPS from 2 to 24 h, by contrast EsMas could be induced by PGN challenge at 2 and 24 h. All these findings indicated that EscSP and EsMas might be involved in the innate immune defenses in E. sinensis.
丝氨酸蛋白酶（SPs）或 SP 同源物（SPHs），包括夹域 SPs（cSPs）或 SPHs（cSPHs），在消化、胚胎发育、血淋巴凝固和黑化中发挥着关键作用。在这项研究中，从中华绒螯蟹（Eriocheir sinensis）的肝胰腺中鉴定出一种 cSP（EscSP）和一种类似于果蝇伪装（EsMas）的 SPH。它们都在 N 端具有夹域，EscSP 只有一个夹域，而 EsMas 有七个夹域。EscSP 和 EsMas 的 C 端分别有一个 SP 或 SP 样结构域。与 EscSP 不同的是，由于缺乏 Ser 的催化残基，导致 EsMas 的 SP 活性丧失。组织分布分析表明，EscSP mRNA 主要在肝胰腺、神经和眼柄组织中表达；而 EsMas 转录本主要分布在眼柄、肌肉、神经和血细胞中。在血细胞中，EscSP 在脂多糖（LPS）或肽聚糖（PGN）刺激后显著增加。然而，在 LPS 刺激的血细胞中，EsMas 的表达下调在 2 到 24 小时观察到，相比之下，PGN 刺激可以在 2 和 24 小时诱导 EsMas。所有这些发现表明，EscSP 和 EsMas 可能参与了中华绒螯蟹的先天免疫防御。
