title: Alternative complement pathway of channel catfish (Ictalurus punctatus): molecular characterization, mapping and expression analysis of factors Bf/C2 and Df.
abstract: The complement system is important in both innate and adaptive host defense against microbial infection in vertebrates. It contains three pathways: the classical, alternative, and lectin pathways. Complement component factors B and D are two crucial proteases in the alternative pathway. In this study, the genes of complement factors Bf/C2 and Df from channel catfish, Ictalurus punctatus were identified and characterized. Two complement factor B-related genes, Bf/C2A and Bf/C2B, and factor D gene Df were identified. Phylogenetic analysis suggested that Bf/C2A and Bf/C2B is likely orthologous to factor B and factor C2, respectively. Southern blot results suggested that these three genes are all single-copy genes in the catfish genome. The catfish Bf/C2A, Bf/C2B and Df genes were genetically mapped on linkage group 3, 20 and 29, respectively. Bf/C2A and Bf/C2B are highly expressed in liver and kidney, while Df is highly expressed in gill and spleen. After infection with Edwardsiella ictaluri, the expression of Bf/C2A, Bf/C2B and Df genes were found to be remarkably induced in the gill, liver, spleen and kidney at some sampling times, indicating that these three complement factors play a pivotal role in immune responses after the bacterial infection in catfish.
authors.affiliation: The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, AL 36849, USA.
authors.forename: Zunchun
authors.initials: Z
authors.lastname: Zhou
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Shikai
authors.initials: S
authors.lastname: Liu
authors.forename: Fanyue
authors.initials: F
authors.lastname: Sun
authors.forename: Eric
authors.initials: E
authors.lastname: Peatman
authors.forename: Huseyin
authors.initials: H
authors.lastname: Kucuktas
authors.forename: Ludmilla
authors.initials: L
authors.lastname: Kaltenboeck
authors.forename: Tingting
authors.initials: T
authors.lastname: Feng
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Donghong
authors.initials: D
authors.lastname: Niu
authors.forename: Jianguo
authors.initials: J
authors.lastname: Lu
authors.forename: Geoff
authors.initials: G
authors.lastname: Waldbieser
authors.forename: Zhanjiang
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D011415:Complement Factor B / Q000235:genetics / Q000276:immunology; D011416:Complement Factor D / Q000235:genetics / Q000276:immunology; D003170:Complement Pathway, Alternative / Q000235:genetics / Q000276:immunology; D004756:Enterobacteriaceae Infections / Q000276:immunology / Q000662:veterinary; D005393:Fish Diseases / Q000276:immunology; D018628:Gene Dosage; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D023061:Gene Order; D008040:Genetic Linkage; D007059:Ictaluridae / Q000145:classification / Q000235:genetics* / Q000276:immunology*; D010802:Phylogeny; D016415:Sequence Alignment
chemical_list: D011416:Complement Factor D; D011415:Complement Factor B