| 摘要: |
| 大菱鲆（Scophthalmus maximus）是我国主要的海水养殖鱼类之一。CD55在哺乳动物中是一种补体调控因子，但其在鱼类中的功能未知。本研究探索了大菱鲆CD55（SmCD55）的功能。结果表明，SmCD55由344个氨基酸残基构成，含有一个N端信号肽和3个补体调控蛋白（CCP）功能域。SmCD55基因在大菱鲆多种组织中均有表达，其中，在肌肉中表达量最低，在脑组织的表达量最高。通过原核表达获得了重组的SmCD55（rSmCD55）蛋白，发现rSmCD55能够抑制大菱鲆血清的溶血活性和杀菌活性，表明其负调控补体系统的激活。此外，本研究还发现rSmCD55可以结合包括重要水产病原菌Edwardsiella tarda、Pseudomonas fluorescens、Vibrio anguillarum、Vibrio harveyi和Streptococcus iniae在内的多种细菌，其中与V. harveyi的结合能力最强。以上这些研究结果丰富了鱼类补体系统的理论知识，加深了对鱼类补体激活调控的了解。 |
| 关键词: 大菱鲆 CD55 补体激活 细菌结合 |
| DOI： |
| 分类号: |
| 基金项目:国家重点研发计划项目(2018YFD0900500) |
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| Turbot Scophthalmus maximus CD55 negatively regulates complement activation and binds a variety of bacteria |
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WU Meng1, LI Mo-fei2, SUN Li1
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1.Institute of Oceanology,Chinese Academy of Sciences;2.Tianjin Normal University
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| Abstract: |
| Turbot (Scophthalmus maximus) is one of the main economic fish in China. CD55 is known to be a complement regulator in mammals, but its function in fish is unknown. In this study, we examined the function of turbot CD55 (SmCD55). The results showed that SmCD55 consists of 344 amino acid residues and contains an N-terminal signal peptide and three complement control protein (CCP) domains. SmCD55 was expressed in several tissues of turbot, with the lowest expression level in muscle and the highest expression level in brain. Recombinant SmCD55 (rSmCD55) protein was obtained from a prokaryotic expression system. rSmCD55 significantly inhibited the hemolytic and bactericidal activities of turbot serum, suggesting that rSmCD55 negatively regulated complement activation. In addition, this study found that rSmCD55 could bind to a variety of bacteria, including the aquaculture pathogens Edwardsiella tarda, Pseudomonas fluorescens, Vibrio anguillarum, Vibrio harveyi, and Streptococcus iniae. Of these bacteria, V. harveyi exhibited the strongest binding ability to rSmCD55. These results add new insights into the complement system in fish and promote our understanding of complement activation and regulation in fish. |
| Key words: Scophthalmus maximus CD55 complement regulation bacterial binding |