title: Molecular cloning, characterization of one key molecule of teleost innate immunity from orange-spotted grouper (Epinephelus coioides): serum amyloid A.
abstract: The orange-spotted grouper (Epinephelus coioides), a favorite marine food fish, is widely cultured in China and Southeast Asian countries. However, little is known about its acute phase response (APR) caused by viral diseases. Serum amyloid A (SAA) is a major acute phase protein (APP). In this study, a new SAA homologous (EcSAA) gene was cloned from grouper, E. coioides, by rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA sequence of SAA was 508 bp and contained a 363 bp open reading frame (ORF) coding for a protein of 121 aa. Similar to other fish known SAA genes, the EcSAA gene contained four exons and three introns. Quantitative real-time PCR analysis revealed that EcSAA mRNA is predominately expressed in liver and gill of grouper. Furthermore, the expression of EcSAA was differentially up-regulated in liver after infection with Staphyloccocus aureus, Vibrio vulnificus, Vibrio parahaemolyticus, Saccharomyces cerevisiae and Singapore grouper iridovirus (SGIV). Recombinant EcSAA (rEcSAA) was expressed in Escherichia BL21 (DE3) and purified for mouse anti-EcSAA serum preparation. The rEcSAA fusion protein was demonstrated to bind to all tested bacteria and yeast, and inhibit the replication of SGIV. Overexpression of EcSAA in grouper spleen (GS) cells could also inhibit the replication of SGIV. These results suggest that EcSAA may be an important molecule in the innate immunity of grouper.
authors.affiliation: Key Laboratory of Marine Bio-resources Sustainable Utilization, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China.
authors.forename: Jingguang
authors.initials: J
authors.lastname: Wei
authors.forename: Minglan
authors.initials: M
authors.lastname: Guo
authors.forename: Huasong
authors.initials: H
authors.lastname: Ji
authors.forename: Qiwei
authors.initials: Q
authors.lastname: Qin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000276:immunology; D001424:Bacterial Infections / Q000201:enzymology / Q000276:immunology / Q000662:veterinary; D001492:Bass / Q000235:genetics* / Q000276:immunology; D003001:Cloning, Molecular; D004266:DNA Virus Infections / Q000201:enzymology / Q000276:immunology / Q000662:veterinary; D018076:DNA, Complementary / Q000235:genetics; D005393:Fish Diseases / Q000201:enzymology / Q000276:immunology; D029941:Fish Proteins / Q000235:genetics* / Q000276:immunology; D005786:Gene Expression Regulation; D007113:Immunity, Innate; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012333:RNA, Messenger / Q000235:genetics; D017995:Ranavirus / Q000276:immunology; D012441:Saccharomyces cerevisiae / Q000276:immunology; D016415:Sequence Alignment / Q000662:veterinary; D017422:Sequence Analysis, DNA / Q000662:veterinary; D000685:Serum Amyloid A Protein / Q000235:genetics* / Q000276:immunology
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D000685:Serum Amyloid A Protein