State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China.
State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory for Improved Variety Reproduction of Aquatic Economic Animals, Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China; Southern Laboratory of Ocean Science and Engineering, Zhuhai, 519000, China.
Fish Shellfish Immunol. 2021 Mar;110:75-85. doi: 10.1016/j.fsi.2020.11.008. Epub 2021 Jan 12.
As a lower vertebrate, the immune defense mechanism of fish mainly depends on the innate immune system. Nucleotide-binding oligomerization domain-like receptors (NLRs) are an important class of pattern recognition receptors in the innate immune system. In this study, NOD1 gene was cloned and characterized in Nile tilapia (Oreochromis niloticus). The ORF of Nile tilapia NOD1 gene was 2826 bp long and encoded 941 amino acid residues with a structure of CARD-NACHT-LRRs that was similar to the other counterparts in mammals and fishes. Phylogenetic and synteny analysis showed that NOD1 was conserved among different fishes and existed at least in the early stage of fish evolution. Expression pattern revealed that NOD1 mRNA was constitutively expressed in the tested tissues, while had high expression level in main immune organs and mucosal immune tissues (liver, head kidney, spleen, blood, gill, and intestine). Following Streptococcus agalactiae challenge, Nile tilapia NOD1 mRNA expression levels were altered in immune organs (liver, head kidney, spleen, blood), and the expression pattern was similar in liver, spleen and blood. Furthermore, the ligand recognition and signaling pathway of Nile tilapia NOD1 were also analyzed, it showed that NOD1 could recognize Tri-DAP intracellularly and activated NF-κB signaling pathway. In summary, our results indicated that the Nile tilapia NOD1 may play an important role in innate immune system and provided a basis for the functional study of NOD1 in teleost.
作为一种低等脊椎动物，鱼类的免疫防御机制主要依赖于先天免疫系统。核苷酸结合寡聚化结构域样受体（NLRs）是先天免疫系统中重要的一类模式识别受体。本研究克隆并鉴定了尼罗罗非鱼（Oreochromis niloticus）NOD1 基因。尼罗罗非鱼 NOD1 基因的 ORF 长 2826bp，编码 941 个氨基酸残基，具有 CARD-NACHT-LRRs 的结构，与哺乳动物和鱼类的其他同源物相似。系统进化和共线性分析表明，NOD1 在不同鱼类中保守，并且至少存在于鱼类进化的早期阶段。表达模式显示，NOD1 mRNA 在测试的组织中持续表达，而在主要免疫器官和黏膜免疫组织（肝、头肾、脾、血、鳃和肠）中表达水平较高。在受到无乳链球菌（Streptococcus agalactiae）挑战后，尼罗罗非鱼 NOD1 mRNA 在免疫器官（肝、头肾、脾、血）中的表达水平发生改变，其在肝、脾和血中的表达模式相似。此外，还分析了尼罗罗非鱼 NOD1 的配体识别和信号通路，结果表明 NOD1 可以识别细胞内的三肽-DAP 并激活 NF-κB 信号通路。综上所述，本研究结果表明，尼罗罗非鱼 NOD1 可能在先天免疫系统中发挥重要作用，为研究 NOD1 在硬骨鱼类中的功能提供了基础。
