National Engineering Research Center of Marine Facilities Aquaculture, Marine Science and Technology College, Zhejiang Ocean University, Zhoushan 316004, China.
Scientific Observing and Experimental Station of Fishery Resources for Key Fishing Grounds, MOA, Key Laboratory of Sustainable Utilization of Technology Research, Marine Fisheries Research Institute of Zhejiang, Zhoushan 316021, China.
Fish Shellfish Immunol. 2018 May;76:41-47. doi: 10.1016/j.fsi.2018.02.044. Epub 2018 Feb 24.
Complement component 3 (C3) plays a central role in the complement system whose activation is essential for all the important functions performed by this system. Here, a novel C3 gene, termed Mc-C3, was identified from thick shell mussel (Mytilus coruscus). The deduced Mc-C3 protein possessed the characteristic structure features present in its homologs and contained the A2M_N_2, ANATO, A2M, A2M_comp, A2M_recep, and C345C domains, as well as the C3 convertase cleavage site, thioester motif, and conserved Cys, His, and Glu residues. Mc-C3 gene constitutively expressed in all examined tissues and predominantly expressed in immune-related tissues such as gills, hemocytes and hepatopancreas. After stimulation with lipopolysaccharide or Cu, the expression of Mc-C3 was significantly induced in gills. Further luciferase reporter assays showed the ability for activation of NF-κB signaling transduction of Mc-C3a. Taken together, these results show that C3 may play an essential role in the immune defense of M. coruscus. The present data therefore provide a more detailed insight into the functional activities of the bivalve complement system.
补体成分 3（C3）在补体系统中起着核心作用，其激活对于该系统执行的所有重要功能都是必不可少的。在这里，从厚壳贻贝（Mytilus coruscus）中鉴定出一种新型的 C3 基因，称为 Mc-C3。推导的 Mc-C3 蛋白具有其同源物中存在的特征结构特征，并包含 A2M_N_2、ANATO、A2M、A2M_comp、A2M_recep 和 C345C 结构域，以及 C3 转化酶切割位点、硫酯基序以及保守的 Cys、His 和 Glu 残基。Mc-C3 基因在所有检查的组织中持续表达，并在免疫相关组织（如鳃、血细胞和肝胰腺）中优先表达。用脂多糖或 Cu 刺激后，Mc-C3 在鳃中的表达明显诱导。进一步的荧光素酶报告基因分析表明，Mc-C3a 具有激活 NF-κB 信号转导的能力。综上所述，这些结果表明 C3 可能在厚壳贻贝的免疫防御中发挥重要作用。因此，本数据提供了对双壳类补体系统功能活动的更详细的了解。
