School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China.
School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China.
Fish Shellfish Immunol. 2023 Feb;133:108555. doi: 10.1016/j.fsi.2023.108555. Epub 2023 Jan 18.
Sebastes schlegelii is a kind of fish with great economic values. Recently, with the continuous expansion of aquaculture scale and the continuous improvement of aquaculture density, outbreak of various diseases has caused huge economic losses to its aquaculture industry. Study of fish immune system can help to understand the mechanism of immune response to external pathogens and can promote the development of immune prevention and control methods. Immunoglobulins (Igs) are complex glycoproteins that appear to be unique to the vertebrates that can recognize a wide variety of pathogens and recruit immune cells and molecules to destroy pathogens, which are generated by a series of rearrangement and somatic mutations. We therefore studied the immunoglobulin genes of S. schlegelii in view of their important roles in resisting to external pathogen infections. In this study, the immunoglobulin heavy chain genes (sIgM, mIgM, sIgT, and mIgT) of S. schlegelii were successfully identified and cloned. Phylogenetic analysis showed that the IgM and IgT genes of S. schlegelii were clustered together with homologous genes of other species, indicating that they were highly conserved during the evolutionary process. Collinearity analysis showed that the immunoglobulin genes and their adjacent genes were aligned with zebrafish, Atlantic salmon and tilapia, which further confirmed the conserved immunoglobulin gene of teleost. Expression analysis of healthy tissues showed that the expression levels of sIgM, sIgT and mIgT were the highest in the skin, while mIgM was the highest in spleen. After different bacterial infection, IgM and IgT were significantly expressed in skin and gill, which may be because skin and gill are the first line of defense against the infection pathogens. Subcellular localization showed that the mIgT protein was expressed in both the cell membrane and cytoplasm. Meanwhile, recombinant protein of mIgT was obtained in vitro, which laid a foundation for subsequent protein function studies. These results provide a theoretical basis for understanding the immunity role of immunoglobulin in S. schlegelii.
拟沙丁鱼是一种经济价值很高的鱼类。近年来，随着水产养殖规模的不断扩大和养殖密度的不断提高，各种疾病的爆发给其水产养殖业造成了巨大的经济损失。研究鱼类免疫系统有助于了解免疫对外源病原体的反应机制，并能促进免疫预防和控制方法的发展。免疫球蛋白（Igs）是一种复杂的糖蛋白，似乎是脊椎动物所特有的，能够识别多种病原体，并募集免疫细胞和分子来破坏病原体，这些都是通过一系列重排和体细胞突变产生的。因此，我们研究了拟沙丁鱼的免疫球蛋白基因，因为它们在抵抗外源病原体感染方面起着重要作用。在这项研究中，成功鉴定并克隆了拟沙丁鱼的免疫球蛋白重链基因（sIgM、mIgM、sIgT 和 mIgT）。系统发育分析表明，拟沙丁鱼的 IgM 和 IgT 基因与其他物种的同源基因聚类在一起，表明它们在进化过程中高度保守。共线性分析表明，免疫球蛋白基因及其相邻基因与斑马鱼、大西洋鲑鱼和罗非鱼对齐，进一步证实了硬骨鱼的保守免疫球蛋白基因。健康组织的表达分析表明，sIgM、sIgT 和 mIgT 在皮肤中的表达水平最高，而 mIgM 在脾脏中的表达水平最高。在不同细菌感染后，IgM 和 IgT 在皮肤和鳃中均有显著表达，这可能是因为皮肤和鳃是抵御感染病原体的第一道防线。亚细胞定位表明 mIgT 蛋白在细胞膜和细胞质中均有表达。同时，体外获得了 mIgT 的重组蛋白，为后续的蛋白质功能研究奠定了基础。这些结果为了解免疫球蛋白在拟沙丁鱼中的免疫作用提供了理论依据。
