title: Identification and characterization of C1 inhibitor in Nile tilapia (Oreochromis niloticus) in response to pathogenic bacteria.
abstract: C1 inhibitor (C1INH) is a multi-functional serine protease inhibitor in plasmatic cascades, not only inactivating various proteases, but also regulating both complement and contact system activation. In this study, we described the identification and characterization of a C1INH ortholog from Nile tilapia (Oreochromis niloticus) at molecular, protein and cellular levels. The full-length cDNA of Oreochromis niloticus C1INH (OnC1INH) consisted of 1791 bp of nucleotide sequence encoding polypeptides of 596 amino acids. The deduced protein possessed a serpin domain at the C-terminal domain, and two Ig-like domains in the N-terminal domain with significant homology to teleost. Expression analysis revealed that the OnC1INH was extremely highly expressed in the liver; however, much weakly exhibited in other tissues including spleen, kidney, blood and heart. After the in vivo challenges of the lipopolysaccharide (LPS) and Streptococcus agalactiae, the expression of OnC1INH was significantly up-regulated in liver and spleen at the late phase, which was confirmed at the protein level with immunohistochemical analysis. The up-regulation of OnC1INH expression was also demonstrated in head kidney monocytes/macrophages in vitro stimulated with LPS, Aeromonas hydrophila and Streptococcus agalactiae, which was positively correlated with the protein expression pattern in the culture media. Taken together, the results of this study indicated that OnC1INH might be involved in the immune response of Nile tilapia against to bacterial challenge.
authors.affiliation: Guangdong Provincial Key Laboratory for Health and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, College of Life Science, South China Normal University, Guangdong 510631, PR China.
authors.forename: Mingmei
authors.initials: M
authors.lastname: Ding
authors.affiliation: Guangdong Provincial Key Laboratory for Health and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, College of Life Science, South China Normal University, Guangdong 510631, PR China.
authors.forename: Meng
authors.initials: M
authors.lastname: Chen
authors.affiliation: Guangdong Provincial Key Laboratory for Health and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, College of Life Science, South China Normal University, Guangdong 510631, PR China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Zhong
authors.affiliation: Guangdong Provincial Key Laboratory for Health and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, College of Life Science, South China Normal University, Guangdong 510631, PR China.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Guangdong Provincial Key Laboratory for Health and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, College of Life Science, South China Normal University, Guangdong 510631, PR China.
authors.forename: Shengli
authors.initials: S
authors.lastname: Fu
authors.affiliation: Guangdong Provincial Key Laboratory for Health and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, College of Life Science, South China Normal University, Guangdong 510631, PR China.
authors.forename: Xiaoxue
authors.initials: X
authors.lastname: Yin
authors.affiliation: Guangdong Provincial Key Laboratory for Health and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, College of Life Science, South China Normal University, Guangdong 510631, PR China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Guangdong Provincial Key Laboratory for Health and Safe Aquaculture, Guangdong Provincial Engineering Technology Research Center for Environmentally-Friendly Aquaculture, College of Life Science, South China Normal University, Guangdong 510631, PR China. Electronic address: yjmying@126.com.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Ye
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D023681:Cichlids; D003001:Cloning, Molecular; D003174:Complement C1 Inactivator Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016905:Gram-Negative Bacterial Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D008070:Lipopolysaccharides / Q000502:physiology; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary; D013290:Streptococcal Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D013292:Streptococcus agalactiae / Q000502:physiology
chemical_list: D003174:Complement C1 Inactivator Proteins; D018076:DNA, Complementary; D029941:Fish Proteins; D008070:Lipopolysaccharides; D012333:RNA, Messenger
keywords: C1 inhibitor; Immune response; Monocytes/macrophages; Oreochromis niloticus; Streptococcus agalactiae