College of Fishery, Henan Normal University, Xinxiang, Henan, 453007, China; State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China.
State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China.
Fish Shellfish Immunol. 2020 Jan;96:190-200. doi: 10.1016/j.fsi.2019.11.032. Epub 2019 Nov 22.
Complement is a complex component of innate immune system, playing an important role in defense against pathogens and host homeostasis. The complement system has been comprehensively studied in mammals, however less is known about complement in teleost, especially in tetraploid common carp (Cyprinus carpio). In this study, a total of 110 complement genes were identified and characterized in common carp, which include almost all the homologs of mammalian complement genes. These genes were classified into three pathways (alternative pathways, lectin pathways and classical pathways), similar to those in mammals. Phylogenetic and selection pressure analysis showed that the complement genes were evolving-constrained and the function was conserved. Most of the complement genes were highly expressed in spleen, liver, brain and skin among the tested 12 health tissues of common carp. After Aeromonas hydrophila infection in the common carp, many members of complement genes were activated to bring about an immune response and expressed to against any pathogenic encroachment. Gene expression divergences which were found between two homoeologous genes suggested the functional divergences of the homoeologous genes after the 4R WGD event, revealing the evolutionary fate of the tetraploid common carp after the recent WGD.
补体是先天免疫系统的一个复杂组成部分，在防御病原体和维持宿主内环境稳定方面发挥着重要作用。补体系统在哺乳动物中得到了广泛研究，但在硬骨鱼中，特别是在四倍体鲤鱼（Cyprinus carpio）中，对补体的了解较少。在本研究中，共鉴定和分析了鲤鱼中的 110 种补体基因，这些基因几乎包含了哺乳动物补体基因的所有同源物。这些基因被分为三条途径（替代途径、凝集素途径和经典途径），与哺乳动物的途径相似。系统发育和选择压力分析表明，补体基因受到进化约束，其功能是保守的。在鲤鱼的 12 种健康组织中，大多数补体基因在脾脏、肝脏、大脑和皮肤中表达水平较高。在鲤鱼感染嗜水气单胞菌后，许多补体基因被激活，引发免疫反应，抵抗任何病原体的侵袭。在两个同源基因之间发现的基因表达差异表明，在四倍体化后的 WGD 事件后，同源基因的功能发生了分化，揭示了四倍体鲤鱼在最近的 WGD 后的进化命运。
