title: Interferon regulatory factor 4b (IRF4b) in Japanese flounder, Paralichthys olivaceus: Sequencing, ubiquitous tissue distribution and inducible expression by poly(I:C) and DNA virus.
abstract: Interferon regulatory factor 4 (IRF4) in mammals is known to be critical in regulation of development and functions of lymphomyeloid cell lineages. Recent studies have demonstrated its involvement in immune responses to bacterial and viral challenges in teleosts. In this study, an IRF4 gene was cloned from Japanese flounder (Paralichthys olivaceus) and its expression in response to polyinosinic:polycytidylic acid [poly(I:C)] and lymphocystis disease virus (LCDV) stimulations was studied in vivo. The cloned gene spans over 5.9 kb, comprises eight exons and seven introns and encodes a putative protein of 456 amino acids. The deduced amino acid sequence possesses a conserved DNA-binding domain (DBD), an IRF-association domain (IAD) and a nuclear localization signal (NLS). Phylogenetic analysis clustered it into the teleost IRF4b clade and, thus, it was named Paralichthys olivaceus (Po)IRF4b. The constitutive expression of PoIRF4b transcripts was detectable in all examined organs, with highest levels found in lymphomyeloid-rich tissues. They were induced by both poly(I:C) and LCDV with a similar inducibility in immune or non-immune organs. Two waves of induced expression of PoIRF4b were observed with the two stimuli during a 7-day time course in the immune organs, with the early-phase induction being stronger. The maximum increases of PoIRF4b transcript levels ranged from 1.3 to 4.0-fold and appeared at day 1-5 post-injection depending on different organs and stimuli. In both stimulation cases, the strongest induction was detected in spleen and the weakest in muscle. These results indicate that PoIRF4b may participate in regulation of immune responses of flounders to both RNA and DNA virus infections.
authors.affiliation: First Institute of Oceanography, State Oceanic Administration of China, Qingdao 266061, China.
authors.forename: Dahai
authors.initials: D
authors.lastname: Liu
authors.affiliation: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
authors.forename: Jinjing
authors.initials: J
authors.lastname: Chen
authors.affiliation: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
authors.forename: Mengzhu
authors.initials: M
authors.lastname: Hu
authors.affiliation: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Lou
authors.affiliation: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
authors.forename: Qiuming
authors.initials: Q
authors.lastname: Liu
authors.affiliation: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
authors.forename: Shicui
authors.initials: S
authors.lastname: Zhang
authors.affiliation: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China. Electronic address: huguobin@mail.ouc.edu.cn.
authors.forename: Guobin
authors.initials: G
authors.lastname: Hu
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004266:DNA Virus Infections / Q000276:immunology*; D005393:Fish Diseases / Q000276:immunology*; D005432:Flounder / Q000276:immunology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D050835:Interferon Regulatory Factors / Q000235:genetics*; D007497:Iridoviridae / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology*; D011070:Poly I-C / Q000276:immunology; D017422:Sequence Analysis, DNA; D029961:Zebrafish Proteins / Q000235:genetics
chemical_list: C000616514:IRF4b protein, zebrafish; D050835:Interferon Regulatory Factors; D029961:Zebrafish Proteins; D011070:Poly I-C
keywords: Gene expression; IRF4b; Immune responses; Paralichthys olivaceus; Viral challenges