title: Identification and expression analysis on bactericidal permeability-increasing protein/lipopolysaccharide-binding protein of blunt snout bream, Megalobrama amblycephala.
abstract: Bactericidal permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) belong to the lipid transfer protein/lipopolysaccharide-binding protein family and play a critical role in the innate immune response to Gram-negative bacteria. In the present study, a novel BPI/LBP from blunt snout bream, Megalobrama amblycephala (maBPI/LBP) was isolated by RACE techniques. The open reading frame (ORF) of maBPI/LBP gene encoded a polypeptide of 474 amino acids with a putative 18-aa hydrophobic signal peptide. Structurally, the maBPI/LBP showed highly similar to those of BPI/LBPs from invertebrate and teleost, LBPs and BPIs from mammal, which contained an N-terminal BPI/LBP/CETP domain BPI1 with a LPS-binding domain, a C-terminal BPI/LBP/CETP domain BPI2, and proline-rich domain. The homologous identities of deduced amino acid sequences displayed that the maBPI/LBP possessed significant similarity (96.61% and 90.07%) with those of grass carp and common carp, respectively. The recombinant protein of maBPI/LBP showed effectively kill Gram-negative bacteria. The maBPI/LBP gene was expressed in a wide range of normal tested tissues, with the highest expression levels in the kidney. The experiments revealed that the mRNA expression of maBPI/LBP in spleen considerably up-regulated from 2 h to 8 h post LPS stimulation, and peaked rapidly at 2 h (7.40-fold, P < 0.05), which confirmed that maBPI/LBP was the absolute sensitive to LPS stimulation. Furthermore, the level of maBPI/LBP mRNA expression reached the maximum for a second time at 24 h after LPS stimulation. These results suggested that maBPI/LBP was a constitutive and inducible acute-phase protein contributing to the host immune defense against pathogenic bacterial infection in M. amblycephala. This study will further our understanding of the function of BPI/LBP and the molecular mechanism of innate immunity in teleost.
authors.affiliation: State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China.
authors.forename: Leilei
authors.initials: L
authors.lastname: Tang
authors.affiliation: Department of Operation, Xiangya Hospital, Central South University, Changsha 410008, PR China.
authors.forename: Yinhua
authors.initials: Y
authors.lastname: Liang
authors.affiliation: State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology of the State Education Ministry of China, College of Life Sciences, Hunan Normal University, Changsha 410018, PR China.
authors.forename: Shaojun
authors.initials: S
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China.
authors.forename: Fuyun
authors.initials: F
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China.
authors.forename: Xia
authors.initials: X
authors.lastname: He
authors.affiliation: State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China.
authors.forename: Tianyi
authors.initials: T
authors.lastname: Wang
authors.affiliation: Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Academy of Fishery Sciences, Nanning, Guangxi 530021, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Academy of Fishery Sciences, Nanning, Guangxi 530021, PR China.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhong
authors.affiliation: State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China. Electronic address: andy_yan@csu.edu.cn.
authors.forename: Jinpeng
authors.initials: J
authors.lastname: Yan
mesh_terms: D000209:Acute-Phase Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D001483:Base Sequence; D001798:Blood Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D029941:Fish Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D005399:Fishes / Q000235:genetics / Q000276:immunology; D005880:Gills / Q000378:metabolism; D060226:Head Kidney / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism; D012313:RNA / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D013154:Spleen / Q000276:immunology / Q000378:metabolism; D000099231:Lipopolysaccharide-Binding Protein
chemical_list: D000209:Acute-Phase Proteins; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D002352:Carrier Proteins; D018076:DNA, Complementary; D029941:Fish Proteins; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D012313:RNA; D011994:Recombinant Proteins; D000099231:Lipopolysaccharide-Binding Protein; C021623:bactericidal permeability increasing protein
keywords: Antibacterial activity; BPI/LBP; Immune response; Lipopolysaccharide stimulation; Megalobrama amblycephala