Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan province, PR China; College of Animal Science and Technology, Henan Institute of Science and Technology, Henan province, PR China.
Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan province, PR China.
Fish Shellfish Immunol. 2020 Aug;103:366-376. doi: 10.1016/j.fsi.2020.04.054. Epub 2020 May 19.
Galectin-9, as one of the important PRRs in host, could initiate the immune defense responses through recognizing and binding PAMPs on the surface of invading microorganisms. In this study, a new galectin-9 cDNA was identified and characterized in Qihe crucian carp Carassius auratus (named as CaGal-9). The complete cDNA sequence of CaGal-9 was 1318 bp, with an open reading frame (ORF) of 963 bp encoding 320 amino acids. The predicted CaGal-9 protein contained two non-identical carbohydrate recognition domains (CRDs), which possessed the representative motifs H-NPR and WG-EER to bind with β-galactoside. Based on the RT-qPCR detection, CaGal-9 was ubiquitously expressed at mRNA level in various tested tissues, and predominately expressed in spleen. Upon Aeromonas hydrophila and poly I: C challenge, the expressions of CaGal-9 were remarkably up-regulated in liver, spleen, kidney and head kidney in a time-depended manner. The recombinant CaGal-9 (rCaGal-9), purified from Escherichia coli BL21 (DE3), exhibited strong binding ability with lipopolysaccharide (LPS), peptidoglycan (PGN) and β-Glucan, as well as the examined microorganisms including fungus, Gram-negative bacteria, and Gram-positive bacteria. With regard to the agglutinating activity of rCaGal-9, it could agglutinate erythrocytes of rabbit and crucian carp, and the examined microorganisms. Taken together, in this study, it was suggested that CaGal-9 could play an important role in immune defense against pathogenic microorganisms in C. auratus, which functions as an important PRR to recognize PAMPs and agglutinate pathogenic microorganisms.
半乳糖凝集素-9（Galectin-9）作为宿主中重要的模式识别受体（PRRs）之一，可通过识别和结合入侵微生物表面的病原体相关分子模式（PAMPs）来启动免疫防御反应。在本研究中，鉴定并表征了淇河鲫（Carassius auratus）中的一种新的半乳糖凝集素-9 cDNA（命名为 CaGal-9）。CaGal-9 的完整 cDNA 序列为 1318bp，开放阅读框（ORF）为 963bp，编码 320 个氨基酸。预测的 CaGal-9 蛋白包含两个非同源的糖识别结构域（CRDs），具有代表性的基序 H-NPR 和 WG-EER 以结合β-半乳糖苷。基于 RT-qPCR 检测，CaGal-9 在各种测试组织中以 mRNA 水平广泛表达，在脾脏中表达丰度最高。在受到嗜水气单胞菌和 Poly I:C 刺激后，CaGal-9 在肝脏、脾脏、肾脏和头肾中的表达呈时间依赖性显著上调。从大肠杆菌 BL21（DE3）中纯化的重组 CaGal-9（rCaGal-9）与脂多糖（LPS）、肽聚糖（PGN）和β-葡聚糖以及真菌、革兰氏阴性菌和革兰氏阳性菌等受检微生物具有很强的结合能力。rCaGal-9 具有凝集活性，可凝集兔和鲫鱼的红细胞以及受检的微生物。综上所述，本研究表明，CaGal-9 在鲫鱼抵御病原微生物的免疫防御中可能发挥重要作用，作为一种重要的 PRR 识别 PAMPs 并凝集病原微生物。
