title: Characterization of serum immunoglobulin M of grouper and cDNA cloning of its heavy chain.
abstract: Immunoglobulin M (IgM) from the whole serum of grouper fish, Epinephelus coioides was purified by affinity chromatography using protein A-Sepharose column. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions revealed that the relative molecular masses (Mr) of the equimolar heavy and light chains of IgM were 78,000 and 27,000, respectively. The cDNAs encoding IgM heavy chain comprising its variable (VH) and constant (CH) regions have been cloned and sequenced from a grouper kidney cDNA library by antibody screening method. Five VH (130-142 amino acids) and four CH (450-454 amino acids) families were identified. The variable and constant regions were conserved with their putative domains. All the four constant region domains (CH1-CH2-CH3-CH4) contained each three conserved cysteine residues, which are considered to form the inter- and intra-chain disulfide bridges. There were three carbohydrate acceptor sites in the constant region. In general, the pattern of IgM gene organization seems to resemble that of other teleosts. Moreover, the CH genes in grouper IgM occur as multifamily as reported in Atlantic salmon and common carp.
authors.affiliation: Department of Food Science, National Kinmen Institute of Technology, Kinmen, Taiwan.
authors.forename: Chao-An
authors.initials: CA
authors.lastname: Cheng
authors.forename: Joseph Abraham Christopher
authors.initials: JA
authors.lastname: John
authors.forename: Ming-Shan
authors.initials: MS
authors.lastname: Wu
authors.forename: Chiou-Yueh
authors.initials: CY
authors.lastname: Lee
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Lin
authors.forename: Cheng-Hui
authors.initials: CH
authors.lastname: Lin
authors.forename: Chi-Yao
authors.initials: CY
authors.lastname: Chang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002846:Chromatography, Affinity / Q000662:veterinary; D016000:Cluster Analysis; D007127:Immunoglobulin Constant Regions / Q000737:chemistry / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry / Q000235:genetics*; D007075:Immunoglobulin M / Q000097:blood / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D007135:Immunoglobulin Variable Region / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D010473:Perciformes / Q000235:genetics* / Q000276:immunology*; D010802:Phylogeny; D012313:RNA / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein
chemical_list: D007127:Immunoglobulin Constant Regions; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region; D012313:RNA