Strait Institute of Flexible Electronics (SIFE, Future Technologies), Fujian Normal University, Fuzhou, 350117, Fujian, China; Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural, Fisheries College, Jimei University, Xiamen, 361021, China.
Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural, Fisheries College, Jimei University, Xiamen, 361021, China.
Fish Shellfish Immunol. 2023 Nov;142:109044. doi: 10.1016/j.fsi.2023.109044. Epub 2023 Aug 30.
Galectins are a family of evolutionarily conserved lectins that contain carbohydrate recognition domains (CRDs) specifically recognizing β-galactoside. Galectin-9 plays a crucial role in various biological processes during pathogenic infections. In a previous study, galectin-9 was identified as a candidate gene for resistance to Vibrio harveyi disease in yellow drum using a genome-wide association study (GWAS) analysis. In this study, a galectin-9 gene was identified from Nibea albiflora and named YdGal-9. The mRNA transcripts of YdGal-9 were distributed in all the detected tissues and the highest level was found in the kidney. The subcellular localization of YdGal-9-EGFP proteins was observed in both nucleus and cytoplasm in the kidney cells of N. albiflora. The expression of YdGal-9 in the brain increased significantly after infection with Vibrio harveyi. The red blood cells from rabbits, Larimichthys crocea, and N. albiflora were agglutinated by the purified recombinant YdGal-9 proteins. The results of the agglutination activity of deletion mutants of YdGal-9 proved that the conserved sugar binding motifs (H-NPR and WG-EE-) were critical for YdGal-9's agglutination activity. In addition, YdGal-9 killed some gram-negative bacteria by inducing cell wall destruction including Pseudomonas plecoglossicida, Aeromonas hydrophila, Escherichia coli, V. parahemolyticus, V. harveyi, and V. alginolyticus. Taken together, these results suggested that the YdGal-9 protein of N. albiflora played a vital role in fighting bacterial infections.
半乳糖凝集素是一类进化上保守的凝集素，包含特定识别β-半乳糖苷的碳水化合物识别结构域（CRD）。半乳糖凝集素-9 在致病感染过程中的各种生物学过程中发挥着关键作用。在之前的研究中，使用全基因组关联研究（GWAS）分析，半乳糖凝集素-9 被鉴定为黄姑鱼抵抗哈维氏弧菌病的候选基因。在本研究中，从白姑鱼中鉴定出一个半乳糖凝集素-9 基因，并将其命名为 YdGal-9。YdGal-9 的 mRNA 转录本分布在所有检测到的组织中，在肾脏中表达水平最高。在白姑鱼肾脏细胞中观察到 YdGal-9-EGFP 蛋白的亚细胞定位存在于细胞核和细胞质中。感染哈维氏弧菌后，白姑鱼大脑中的 YdGal-9 表达显著增加。兔、大黄鱼和白姑鱼的红细胞被纯化的重组 YdGal-9 蛋白凝集。YdGal-9 缺失突变体的凝集活性结果表明，保守的糖结合基序（H-NPR 和 WG-EE-）对半乳糖凝集素-9 的凝集活性至关重要。此外，YdGal-9 通过诱导细胞壁破坏杀死了一些革兰氏阴性菌，包括荧光假单胞菌、嗜水气单胞菌、大肠杆菌、副溶血弧菌、哈维氏弧菌和溶藻弧菌。综上所述，这些结果表明白姑鱼 YdGal-9 蛋白在抵抗细菌感染中发挥着重要作用。
