title: Molecular genomic- and transcriptional-aspects of a teleost TRAF6 homolog: Possible involvement in immune responses of Oplegnathus fasciatus against pathogens.
abstract: Tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6) is a crucial docking molecule for TNFR superfamily and Interleukin-1 receptor/Toll-like receptor (IL-1R/TLR) superfamily. As an adaptor protein in pathogen-induced signaling cascades, TRAF6 modulates both adaptive- and innate-immunity. In order to understand the immune responses of teleost TRAF6, Oplegnathus fasciatus TRAF6-like gene (OfTRAF6) was identified and characterized. Genomic length of OfTRAF6 (4 kb), obtained by means of a genomic BAC library, spanned seven exons which represented a putative coding sequence of 1716 bp and encoded 571 amino acids (aa) with an estimated molecular weight of 64 kDa. This putative protein demonstrated the classical tetra-domain architecture composed of a zinc finger RING-type profile, two zinc finger TRAF-type profiles, a coiled-coil region and a MATH domain. While the sequence similarity with human TRAF6 was 66.5%, OfTRAF6 shared a higher overall similarity with teleost homologs (∼75-92%). Phylogeny of TRAF-family was examined and TRAF6-subfamily appeared to be the precursor of other subfamilies. In addition, the clustering pattern confirmed that OfTRAF6 is a novel member of TRAF6subfamily. Based on comparative genomic analysis, we found that vertebrate TRAF6 exhibits two distinct structures in teleost and tetrapod lineages. An intron-loss event has probably occurred in TRAF6 gene during the evolution of tetrapods from teleosts. Inspection of putative OfTRAF6 promoter revealed the presence of several immune responsive transcription factor binding sites. Real-time qPCR assay detected OfTRAF6 transcripts in eleven juvenile fish tissues with higher levels in peripheral blood cells followed by liver. Putative role of OfTRAF6 in response to flagellin, LPS, poly I:C, pathogenic bacteria (Edwardsiella tarda and Streptococcus iniae) and rock bream iridovirus (RBIV) was profiled in different tissues and OfTRAF6 revealed up-regulated transcript levels. Altogether, these findings implicate that OfTRAF6 is not only involved in flagellin-induced signaling cascade, but also contributes to the antibacterial- and antiviral-responses.
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 Self-Governing Province 690-756, Republic of Korea.
authors.forename: Navaneethaiyer
authors.initials: N
authors.lastname: Umasuthan
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 Self-Governing Province 690-756, Republic of Korea.
authors.forename: S D N K
authors.initials: SD
authors.lastname: Bathige
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: Kasthuri Saranya
authors.initials: KS
authors.lastname: Revathy
authors.affiliation: Biotechnology Research Division, Fisheries Research and Development Institute, 408-1, Sirang-ri, Gijang-up, Gigang-gun, Busan 619-705, Republic of Korea.
authors.forename: Bo-Hye
authors.initials: BH
authors.lastname: Nam
authors.affiliation: Division of Marine Environment and Bioscience, Korea Maritime University, Busan 606-791, Republic of Korea.
authors.forename: Cheol Young
authors.initials: CY
authors.lastname: Choi
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 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: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D005408:Flagellin / Q000378:metabolism; D040461:Gene Components; D020869:Gene Expression Profiling / Q000662:veterinary; D007113:Immunity, Innate / Q000235:genetics*; D016013:Likelihood Functions; D008099:Liver / Q000378:metabolism; D008957:Models, Genetic; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000235:genetics; D010473:Perciformes / Q000235:genetics / Q000276:immunology*; D010802:Phylogeny; D012333:RNA, Messenger / Q000097:blood / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA / Q000662:veterinary; D015398:Signal Transduction / Q000276:immunology*; D048029:TNF Receptor-Associated Factor 6 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D009841:Oligonucleotides; D012333:RNA, Messenger; D048029:TNF Receptor-Associated Factor 6; D005408:Flagellin
keywords: Flagellin (FLA); Genomic evolution; Immune responses; Putative promoter; Tumor necrosis factor receptor-associated factor 6 (TRAF6)