title: Insights into molecular profiles and genomic evolution of an IRAK4 homolog from rock bream (Oplegnathus fasciatus): immunogen- and pathogen-induced transcriptional expression.
abstract: As a pivotal signaling mediator of toll-like receptor (TLR) and interleukin (IL)-1 receptor (IL-1R) signaling cascades, the IL-1R-associated kinase 4 (IRAK4) is engaged in the activation of host immunity. This study investigates the molecular and expressional profiles of an IRAK4-like homolog from Oplegnathus fasciatus (OfIRAK4). The OfIRAK4 gene (8.2 kb) was structured with eleven exons and ten introns. A putative coding sequence (1395bp) was translated to the OfIRAK protein of 464 amino acids. The deduced OfIRAK4 protein featured a bipartite domain structure composed of a death domain (DD) and a kinase domain (PKc). Teleost IRAK4 appears to be distinct and divergent from that of tetrapods in terms of its exon-intron structure and evolutionary relatedness. Analysis of the sequence upstream of translation initiation site revealed the presence of putative regulatory elements, including NF-κB-binding sites, which are possibly involved in transcriptional control of OfIRAK4. Quantitative real-time PCR (qPCR) was employed to assess the transcriptional expression of OfIRAK4 in different juvenile tissues and post-injection of different immunogens and pathogens. Ubiquitous basal mRNA expression was widely detected with highest level in liver. In vivo flagellin (FLA) challenge significantly intensified its mRNA levels in intestine, liver and head kidney indicating its role in FLA-induced signaling. Meanwhile, up-regulated expression was also determined in liver and head kidney of animals challenged with potent immunogens (LPS and poly I:C) and pathogens (Edwardsiella tarda and Streptococcus iniae and rock bream iridovirus (RBIV)). Taken together, these data implicate that OfIRAK4 might be engaged in antibacterial and antiviral immunity in 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; Fish Vaccine Research Center, Jeju National University, Jeju Special 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 Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: S D N K
authors.initials: SD
authors.lastname: Bathige
authors.affiliation: Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Ilson
authors.initials: I
authors.lastname: Whang
authors.affiliation: Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Bong-Soo
authors.initials: BS
authors.lastname: Lim
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 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: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001492:Bass / Q000235:genetics* / Q000276:immunology; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D020609:Edwardsiella tarda / Q000502:physiology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D016678:Genome; D007113:Immunity, Innate; D053592:Interleukin-1 Receptor-Associated Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017994:Iridovirus / Q000502:physiology; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D011070:Poly I-C / Q000008:administration & dosage; D011401:Promoter Regions, Genetic; D013291:Streptococcus / Q000502:physiology
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D008070:Lipopolysaccharides; D053592:Interleukin-1 Receptor-Associated Kinases; D011070:Poly I-C
keywords: Flagellin (FLA); Genomic evolution; IL-1R-associated kinase 4 (IRAK4); Immune responses; Putative promoter