East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture, Shanghai, 200090, China; Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, Nanjing, 210046, China.
Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, Nanjing, 210046, China.
Fish Shellfish Immunol. 2018 May;76:380-390. doi: 10.1016/j.fsi.2018.02.032. Epub 2018 Feb 21.
Galactoside-binding lectins, also known as galectins, play crucial roles in innate immune response in invertebrates. In this study, three cDNA sequences from Hyriopsis cumingii were identified and collectively called HcGalec genes. Each of the three deduced HcGalec proteins contained a galactose-binding lectin domain or a GLECT domain. All the three HcGalec genes are mainly present in the hepatopancreas and gills, and their expression is induced at 24 h after bacterial challenge. Three recombinant HcGalec proteins can bind and agglutinate (Ca-dependent) various microorganisms, including Gram-positive and Gram-negative bacteria. These proteins can attach to mannan and peptidoglycan. Meanwhile, the expression of the three HcGalec genes in the gills were significantly down-regulated after dsRNA interference (HcGalec1-RNAi, HcGalec2-RNAi, and HcGalec3-RNAi) and Vibrio parahaemolyticus injection. The expression levels of some antimicrobial peptides, including lysozyme 1 and lysozyme 2, were also markedly decreased after dsRNA interference. Overall, these results suggested that these three HcGalec proteins may function as potential receptors participating in the innate immune responses of H. cumingii against bacterial infection.
半乳糖结合凝集素，也称为半乳凝素，在无脊椎动物的先天免疫反应中发挥着关键作用。在这项研究中，从三角帆蚌中鉴定出三个 cDNA 序列，并将其统称为 HcGalec 基因。这三种推导的 HcGalec 蛋白都包含一个半乳糖结合凝集素结构域或 GLECT 结构域。所有三种 HcGalec 基因主要存在于肝胰腺和鳃中，其表达在细菌攻毒后 24 小时被诱导。三种重组 HcGalec 蛋白可以结合和凝集（Ca 依赖性）各种微生物，包括革兰氏阳性菌和革兰氏阴性菌。这些蛋白可以附着在甘露聚糖和肽聚糖上。同时，在 dsRNA 干扰（HcGalec1-RNAi、HcGalec2-RNAi 和 HcGalec3-RNAi）和副溶血弧菌注射后，三种 HcGalec 基因在鳃中的表达显著下调。一些抗菌肽（包括溶菌酶 1 和溶菌酶 2）的表达水平在 dsRNA 干扰后也明显下降。总的来说，这些结果表明，这三种 HcGalec 蛋白可能作为潜在的受体参与三角帆蚌对细菌感染的先天免疫反应。
