title: Genomic characterization and transcriptional evidence for the involvement of complement component 7 in immune response of rock bream (Oplegnathus fasciatus).
abstract: The complement component 7 (C7) is the central mediator of pathogenic attack at the membrane surface and its binding to the C5b-7 complex triggers cytolytic signaling. In this study, C7 of rock bream (Oplegnathus fasciatus) was identified (Rb-C7) and characterized at the genomic level. The Rb-C7 gene contains 18 exons and 17 introns and is composed of a 2490 bp complete open reading frame (ORF). The encoded polypeptide (830 amino acids) contains a number of well-conserved C7 signature domains. Important putative transcription factor binding sites, including those for NF-κB, SP-1, C/EBP, AP-1 and OCT-1, are present in the 5'-flanking region of Rb-C7. Phylogenetic analysis revealed a close proximity of Rb-C7 with the orthologues in tilapia and Japanese flounder. Quantitative real-time PCR (qPCR) analysis confirmed constitutive Rb-C7 expression throughout all the examined tissue of healthy rock bream, with highest expression in liver. In immune challenge experiment, Rb-C7 expression was up-regulated in head kidney and liver in response to Edwardsiella tarda, Streptococcus iniae, lipopolysaccharide and rock bream iridovirus (RBIV). Furthermore, significant increases of both intracellular expression level and the number of Rb-C7-expressing cells were detected by in situ hybridization assay in head kidney and liver tissues upon E. tarda infection. These results suggested that Rb-C7 is lytic pathway gene in complement system and its transcriptional regulation may be an important immune response in pathogenic defense mechanism of rock bream.
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea.
authors.forename: W D Niroshana
authors.initials: WD
authors.lastname: Wickramaarachchi
authors.forename: Ilson
authors.initials: I
authors.lastname: Whang
authors.forename: Eunmi
authors.initials: E
authors.lastname: Kim
authors.forename: Bong-Soo
authors.initials: BS
authors.lastname: Lim
authors.forename: Hyung-Bok
authors.initials: HB
authors.lastname: Jeong
authors.forename: Mahanama
authors.initials: M
authors.lastname: De Zoysa
authors.forename: Myung-Joo
authors.initials: MJ
authors.lastname: Oh
authors.forename: Sung-Ju
authors.initials: SJ
authors.lastname: Jung
authors.forename: Sang-Yeob
authors.initials: SY
authors.lastname: Yeo
authors.forename: Sung Yeon
authors.initials: SY
authors.lastname: Kim
authors.forename: Hae-Chul
authors.initials: HC
authors.lastname: Park
authors.forename: Jehee
authors.initials: J
authors.lastname: Lee
mesh_terms: D000818:Animals; D001665:Binding Sites; D003184:Complement C7 / Q000145:classification / Q000235:genetics / Q000276:immunology*; D020609:Edwardsiella tarda / Q000276:immunology; D004756:Enterobacteriaceae Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D005091:Exons; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology; D029941:Fish Proteins / Q000145:classification / Q000235:genetics / Q000276:immunology*; D005786:Gene Expression Regulation; D016678:Genome; D007438:Introns; D016366:Open Reading Frames; D010473:Perciformes / Q000276:immunology* / Q000382:microbiology; D010802:Phylogeny; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000235:genetics / Q000276:immunology; D014158:Transcription, Genetic / Q000276:immunology*
chemical_list: D003184:Complement C7; D029941:Fish Proteins; D014157:Transcription Factors