title: Cloning and expression analysis of interferon regulatory factor 7 (IRF-7) in turbot, Scophthalmus maximus.
abstract: Interferon regulatory factor (IRF) 7 is known as the master regulator of type I interferon (IFN)-dependent immune responses in mammals. In this study, the cDNA and genomic sequences of turbot (Scophthalmus maximus) IRF-7 (SmIRF-7) were cloned and found to encode a putative protein of 439 amino acids. The gene is composed of 10 exons and 9 introns similar to known IRF-7 genes of fish. The SmIRF-7 shows the highest amino acid identity of 49.0-80.3% to fish IRF-7 and possesses a DNA-binding domain (DBD), an IRF association domain (IAD) and a serine-rich domain (SRD) of vertebrate IRF-7. In addition, the tryptophan cluster of SmIRF-7 DBD consists of only four tryptophans, which is a characteristic unique to all fish IRF-7 members. The SmIRF-7 transcripts were expressed constitutively in all analyzed tissues of healthy turbot, with higher levels observed in immune relevant tissues. Gene expressions of SmIRF-7 and Mx were monitored over a 7-day time course by quantitative real time PCR in head kidney and muscle of turbot challenged with turbot reddish body iridovirus (TRBIV), which is a prevalent viral pathogens in farmed turbot in China. Both genes were up-regulated by TRBIV although their inducibility was much weaker in the muscle. The peak levels of SmIRF-7 transcripts were detected at day 2 post-infection in the two organs with a 12- and 4.5-fold increase, respectively. Further, the Mx showed two waves of induced expression and the maximum expression of SmIRF-7 arose earlier than the second wave of the Mx expression in both organs. These findings contribute to an understanding of functions of SmIRF-7 in antiviral response.
authors.affiliation: College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China. huguobin@mail.ouc.edu.cn
authors.forename: Guobin
authors.initials: G
authors.lastname: Hu
authors.forename: Jun
authors.initials: J
authors.lastname: Xia
authors.forename: Huimin
authors.initials: H
authors.lastname: Lou
authors.forename: Qiuming
authors.initials: Q
authors.lastname: Liu
authors.forename: Jingyun
authors.initials: J
authors.lastname: Lin
authors.forename: Xiangyan
authors.initials: X
authors.lastname: Yin
authors.forename: Xianzhi
authors.initials: X
authors.lastname: Dong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D005412:Flatfishes / Q000235:genetics* / Q000276:immunology*; D020869:Gene Expression Profiling; D050839:Interferon Regulatory Factor-7 / Q000235:genetics*; D008969:Molecular Sequence Data; D009928:Organ Specificity; D016415:Sequence Alignment
chemical_list: D050839:Interferon Regulatory Factor-7