title: Diversity of complement factor B/C2 in the common carp (Cyprinus carpio): three isotypes of B/C2-A expressed in different tissues.
abstract: Complement factor B and C2 are two critical proteases for complement activation. Some bony fish have been reported to possess duplicated genes for B/C2, but there is no direct evidence regarding possible functional divergence. Here, we report the isolation of the second and third isotypes of carp B/C2-A, a close relative of other bony fish B reported to date, and designated B/C2-A2 and B/C2-A3. B/C2-A1 (previously reported B/C2-A) and B/C2-A2 share 78% amino acid identity and are synthesized mainly in hepatopancreas. On the other hand, B/C2-A3 showed less (approximately 60%) sequence identity with the other two isotypes. It was expressed mainly in kidney and spleen, and was up-regulated after injection of carp with scleroglucan or sodium alginate, known immunostimulants for fish. Phylogenetic analysis suggests that B/C2-A3 diverged before separation of carp and zebrafish. B/C2-A3 represent a novel B/C2-lineage functioning as an acute phase reactant in cyprinid fish.
authors.affiliation: Laboratory of Marine Biological Chemistry, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Hakozaki, Fukuoka, 812 8581, Japan. miki_n@agr.kyushu-u.ac.jp
authors.forename: Miki
authors.initials: M
authors.lastname: Nakao
authors.forename: Momoe
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Mika
authors.initials: M
authors.lastname: Nakazawa
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Fujiki
authors.forename: Tomoki
authors.initials: T
authors.lastname: Yano
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002347:Carps / Q000235:genetics / Q000276:immunology*; D003176:Complement C3 / Q000737:chemistry / Q000235:genetics*; D011415:Complement Factor B / Q000737:chemistry / Q000235:genetics*; D018076:DNA, Complementary / Q000737:chemistry; D005786:Gene Expression Regulation / Q000276:immunology; D015723:Gene Library; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D020033:Protein Isoforms / Q000235:genetics; D012313:RNA / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
chemical_list: D003176:Complement C3; D018076:DNA, Complementary; D020033:Protein Isoforms; D012313:RNA; D011415:Complement Factor B