title: Genomic characterization and expression pattern of Bf/C2 and C4 in miiuy croaker and molecular evolution analysis on mammals and fishes.
abstract: 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.
authors.affiliation: Laboratory of Fish Biogenetics & Immune Evolution, College of Marine Science, Zhejiang Ocean University, Zhoushan 316022, China.
authors.forename: Shanchen
authors.initials: S
authors.lastname: Wang
authors.affiliation: Laboratory of Fish Biogenetics & Immune Evolution, College of Marine Science, Zhejiang Ocean University, Zhoushan 316022, China.
authors.forename: Rixin
authors.initials: R
authors.lastname: Wang
authors.affiliation: Laboratory of Fish Biogenetics & Immune Evolution, College of Marine Science, Zhejiang Ocean University, Zhoushan 316022, China. Electronic address: tianjunxu@163.com.
authors.forename: Tianjun
authors.initials: T
authors.lastname: Xu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001424:Bacterial Infections / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000662:veterinary*; D001483:Base Sequence; D001499:Bayes Theorem; D003175:Complement C2 / Q000235:genetics / Q000378:metabolism*; D003181:Complement C4 / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D016013:Likelihood Functions; D008099:Liver / Q000378:metabolism; D008957:Models, Genetic; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010473:Perciformes; D010802:Phylogeny; D011487:Protein Conformation; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D003175:Complement C2; D003181:Complement C4; D017931:DNA Primers
keywords: Bf/C2; C4; Expression pattern; Miiuy croaker; Molecular evolution