title: Identification of a C-reactive protein like homologue from black rockfish (Sebastes schlegelii) evidencing its potent anti-microbial properties at molecular level.
abstract: Pentraxins are a family of evolutionary conserved proteins that contains two main members, namely c-reactive proteins (CRPs) and serum amyloid P (SAP), which are involved in acute phase responses in animals. In this study, a cDNA sequence of a CRP-like molecule was identified from a previously constructed black rockfish cDNA database (RfCRP) and subsequently characterized at its molecular level. The complete coding region of RfCRP is 672 bp in length, and encodes a protein containing 224 amino acids with a predicted molecular mass of 25.19 kDa. Analysis of its derived amino acid sequence enabled typical features of pentraxin family members to be identified, including the pentraxin family signature in RfCRP. Results from multiple sequence alignment suggest the conservation of functionally important residues in RfCRP. According to the phylogenetic reconstruction that was generated using different pentraxin counterparts from different taxa, RfCRP shares a common vertebrate ancestral origin and most closely clusters with marine teleostan CRP. Furthermore, recombinant RfCRP demonstrated Ca(2+)-dependent agglutination activity against Escherichia coli, which could be completely inhibited in the presence of carbohydrate based ligands. Moreover, recombinant RfCRP also exhibited anti-bacterial activity against both E. coli and Streptococcus iniae. In addition, qPCR analysis indicated that RfCRP is ubiquitously expressed in physiologically important tissues, with pronounced expression in the spleen. After healthy fish were treated with polysaccharides or live S. iniae, basal expression of RfCRP was significantly upregulated in spleen and head kidney tissues. Collectively, our results suggest that RfCRP may be important in host anti-bacterial defense, and it might potentially participate in the acute phase of infection.
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Don Anushka Sandaruwan
authors.initials: DA
authors.lastname: Elvitigala
authors.affiliation: Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wan
authors.affiliation: Genetics & Breeding Research Center, National Fisheries Research & Development Institute, Geoje 656-842, Republic of Korea.
authors.forename: Hyun Chul
authors.initials: HC
authors.lastname: Kim
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea. Electronic address: jehee@jejunu.ac.kr.
authors.forename: Jehee
authors.initials: J
authors.lastname: Lee
mesh_terms: D000371:Agglutination / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002097:C-Reactive Protein / Q000031:analogs & derivatives / Q000235:genetics / Q000276:immunology*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004926:Escherichia coli / Q000276:immunology*; D029941:Fish Proteins / Q000235:genetics / Q000276:immunology; D020869:Gene Expression Profiling; D060226:Head Kidney / Q000378:metabolism; D008969:Molecular Sequence Data; D010473:Perciformes / Q000235:genetics / Q000276:immunology*; D011134:Polysaccharides / Q000276:immunology*; D016415:Sequence Alignment; D013154:Spleen / Q000378:metabolism; D013291:Streptococcus / Q000276:immunology*
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D011134:Polysaccharides; D002097:C-Reactive Protein
keywords: Antibacterial activity; Black rockfish; C-reactive protein; Immune stimulation; Transcriptional modulation