College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China; Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen, 51820, China.
College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China; Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen, 51820, China.
Fish Shellfish Immunol. 2021 Sep;116:74-83. doi: 10.1016/j.fsi.2021.05.014. Epub 2021 May 24.
CD226 interacts with its ligand Necl5 as a costimulatory signal. In this study, we cloned a CD226 from Nile tilapia (Oreochromis niloticus, named OnCD226) and a Necl5 (named OnNecl5). The open reading frame of OnCD226 was 1071 bp, encoding a protein of 356 amino acids. Sequence alignment analysis indicated that OnCD226 contained two Ig-like domains in ectodomain. The open reading frame of OnNecl5 was 1155 bp, encoding a protein of 384 amino acids, and there are three lg-like domains in the extracellular domain. In healthy tilapia, OnCD226 was distributed in all tested tissues and relatively higher in the brain, while OnNecl5 was relatively higher in the skin. After Streptococcus agalactiae infection, OnCD226 has the same up-regulated expression pattern as OnNecl5 in different tissues. After HKLs stimulation with S. agalactiae and Poly I:C, respectively. OnCD226 was significantly up-regulated (0.01 < p < 0.05) at 12 h and extremely significant up-regulation was observed (p < 0.01) at 48 h and 96 h, the peak was observed at 96 h after stimulation by S. agalactiae. After stimulation by Poly I:C, OnCD226 expression was extremely significant (p < 0.01) at 72 h and 96 h, the peak was observed at 96 h. After stimulation by Keyhole limpet hemocyanin (KLH), a classical T cell-dependent antigen, the expression of OnCD226 was significantly up-regulated in blood, head kidney, spleen, and thymus. Moreover, when compared with the first challenge, the gene expression of OnCD226 which response to the second challenge was up-regulated earlier. Subcellular co-localization studies showed that OnCD226 and OnNecl5 were distributed mainly in the cytomembrane. Yeast two-hybrid results, indicated a strong interaction between OnCD226 and OnNecl5. These results suggested that OnCD226 plays an important role during pathogens infection, and the interaction between CD226 and Necl5 is conserved in Nile tilapia.
CD226 与配体 Necl5 相互作用作为一种共刺激信号。在本研究中，我们从尼罗罗非鱼（Oreochromis niloticus）克隆了 CD226（命名为 OnCD226）和 Necl5（命名为 OnNecl5）。OnCD226 的开放阅读框为 1071bp，编码 356 个氨基酸的蛋白质。序列比对分析表明，OnCD226 的胞外域含有两个 Ig 样结构域。OnNecl5 的开放阅读框为 1155bp，编码 384 个氨基酸，胞外域有三个 Ig 样结构域。在健康罗非鱼中，OnCD226 分布于所有检测的组织中，在脑中的相对含量较高，而 OnNecl5 在皮肤中的相对含量较高。在哈维弧菌感染后，不同组织中 OnCD226 的表达与 OnNecl5 呈相同的上调模式。在 HKL 分别用哈维弧菌和 Poly I:C 刺激后，OnCD226 在 12h 时显著上调（0.01<p<0.05），在 48h 和 96h 时极显著上调（p<0.01），刺激后 96h 达到峰值。用 Poly I:C 刺激后，OnCD226 的表达在 72h 和 96h 时极显著（p<0.01），在 96h 时达到峰值。在用 Keyhole limpet hemocyanin（KLH），一种经典的 T 细胞依赖性抗原刺激后，血液、头肾、脾脏和胸腺中的 OnCD226 表达显著上调。此外，与第一次刺激相比，第二次刺激时 OnCD226 基因的表达上调更早。亚细胞共定位研究表明，OnCD226 和 OnNecl5 主要分布在细胞膜上。酵母双杂交结果表明，OnCD226 和 OnNecl5 之间存在强烈的相互作用。这些结果表明，OnCD226 在病原体感染过程中发挥重要作用，并且 CD226 和 Necl5 之间的相互作用在尼罗罗非鱼中是保守的。
