Wang Jingchao, Wang Qian, Chen Yadong, Wang Linqing, Zhao Aiyun, Sha Zhenxia
College of Life Science, Qingdao University, Qingdao, 266071, China.
Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, China.
Fish Shellfish Immunol. 2020 Sep;104:101-110. doi: 10.1016/j.fsi.2020.05.042. Epub 2020 May 25.
The ninth complement component (C9) is a terminal complement component (TCC) that is involved in creating the membrane attack complex (MAC) on the target cell surface. In this study, the CsC9 (C9 of Cynoglossus semilaevis) cDNA sequence was cloned and characterized. The full-length CsC9 cDNA measured 2,150 bp, containing an open reading frame (ORF) of 1,803 bp, a 5'-untranslated region (UTR) of 24 bp and a 3'-UTR of 323 bp. A domain search revealed that the CsC9 protein contains five domains, including two TSP1s, an LDLRA, an EGF, and a MACPF. Quantitative real-time PCR analysis showed that CsC9 at the mRNA level was expressed in all the tested tissues, with the highest expression being observed in the liver. CsC9 expression is significantly upregulated in the tested tissues after challenge with Vibrio anguillarum. To further characterize the role of CsC9, peripheral blood mononuclear cells of C. semilaevis were used for transcriptome analysis after incubation with recombinant CsC9 (rCsC9) protein. A total of 3,775 significant differentially expressed genes (DEGs) were identified between the control and the rCsC9-treated group, including 2,063 upregulated genes and 1,712 downregulated genes. KEGG analyses revealed that the DEGs were enriched in cell adhesion molecules, cytokine-cytokine receptor interactions, T cell receptor signaling pathways, B cell receptor signaling pathways and Toll-like receptor signaling pathways. The results of this study indicate that in addition to participating in MAC formation, CsC9 might play multiple roles in the innate and adaptive immunity of C. semilaevis.
第九补体成分（C9）是一种末端补体成分（TCC），参与在靶细胞表面形成膜攻击复合物（MAC）。在本研究中，克隆并鉴定了半滑舌鳎的CsC9（C9）cDNA序列。CsC9 cDNA全长2150 bp，包含一个1803 bp的开放阅读框（ORF）、一个24 bp的5'非翻译区（UTR）和一个323 bp的3'UTR。结构域搜索显示，CsC9蛋白包含五个结构域，包括两个TSP1、一个LDLRA、一个EGF和一个MACPF。实时定量PCR分析表明，CsC9在mRNA水平上在所检测的所有组织中均有表达，其中在肝脏中表达最高。在用鳗弧菌攻击后，所检测组织中CsC9的表达显著上调。为了进一步表征CsC9的作用，将半滑舌鳎的外周血单核细胞与重组CsC9（rCsC9）蛋白孵育后用于转录组分析。在对照组和rCsC9处理组之间共鉴定出3775个显著差异表达基因（DEG），包括2063个上调基因和1712个下调基因。KEGG分析显示，这些DEG富集于细胞粘附分子、细胞因子-细胞因子受体相互作用、T细胞受体信号通路、B细胞受体信号通路和Toll样受体信号通路。本研究结果表明，CsC9除了参与MAC形成外，可能在半滑舌鳎的先天免疫和适应性免疫中发挥多种作用。
