Wang Shanchen, Wang Rixin, Xu Tianjun
Laboratory of Fish Biogenetics & Immune Evolution, College of Marine Science, Zhejiang Ocean University, Zhoushan 316022, China.
Laboratory of Fish Biogenetics & Immune Evolution, College of Marine Science, Zhejiang Ocean University, Zhoushan 316022, China.
Fish Shellfish Immunol. 2014 Aug;39(2):423-31. doi: 10.1016/j.fsi.2014.06.001. Epub 2014 Jun 11.
The complement system plays an important role in both innate and adaptive host defense against the invading microorganisms in vertebrates. It can be activated by three pathways: the classical, alternative and lectin pathways. Bf/C2 and C4, as members of complement, play a pivotal role in the activation of the complement system. In our study, we identified Bf/C2 and C4 genes and genomic structure in miiuy croaker, and expression patterns of Bf/C2 and C4 genes was analyzed. In healthy miiuy croaker tissues, Bf/C2 and C4 genes were found to be ubiquitously expressed in all ten tested tissues. Analysis of expression of Bf/C2 and C4 genes after bacterial infection showed a significant up-regulated in liver. The evolutionary analysis showed that the ancestral lineages of Bf/C2 and C4 genes in mammals and fishes experienced positive selection indicated that the ancestors of mammals and fishes had further evolved to adapt to their environment, respectively. A series of maximum likelihood (ML) methods were used to study the evolution on vertebrates' Bf/C2 and C4 genes. One and five positive selection sites were found in mammals of Bf/C2 and C4 genes, but no positive selection site was found in fishes of Bf/C2 and C4 genes, indicating that Bf/C2 and C4 genes in mammals and fishes underwent different evolutionary patterns.
补体系统在脊椎动物抵御入侵微生物的固有免疫和适应性免疫宿主防御中均发挥着重要作用。它可通过三条途径激活：经典途径、替代途径和凝集素途径。Bf/C2和C4作为补体成员，在补体系统的激活中起关键作用。在我们的研究中，我们鉴定了大黄鱼中的Bf/C2和C4基因及其基因组结构，并分析了Bf/C2和C4基因的表达模式。在健康大黄鱼组织中，发现Bf/C2和C4基因在所有十个检测组织中均广泛表达。细菌感染后Bf/C2和C4基因表达分析显示肝脏中显著上调。进化分析表明，哺乳动物和鱼类中Bf/C2和C4基因的祖先谱系经历了正选择，这表明哺乳动物和鱼类的祖先分别进一步进化以适应其环境。使用了一系列最大似然（ML）方法来研究脊椎动物Bf/C2和C4基因的进化。在哺乳动物的Bf/C2和C4基因中发现了1个和5个正选择位点，但在鱼类的Bf/C2和C4基因中未发现正选择位点，这表明哺乳动物和鱼类中的Bf/C2和C4基因经历了不同的进化模式。
