Molecular cloning and characterization of interferon regulatory factor 9 (IRF9) in Japanese flounder, Paralichthys olivaceus.
Interferon regulatory factor 9 (IRF9) in mammals is known to be involved in antiviral response. In this study, we studied the structure, mRNA tissue distribution and regulation of IRF9 from Japanese flounder, Paralichthys olivaceus. The cDNA sequence of IRF9 is 3305 bp long, containing an open reading frame (ORF) of 1308 bp that encodes a peptide of 435 amino acids. The predicted protein sequence shares 33.7-72.0% identity to other fish IRF9s. Japanese flounder IRF9 possesses a DNA-binding domain (DBD), an IRF association domain (IAD), two nuclear localization signals (NLSs) and a proline-rich domain (PRD). The IRF9 transcripts were detectable in all examined tissues of healthy Japanese flounders, with higher levels in the head kidney, kidney, liver and spleen. The IRF9 mRNA levels were up-regulated in the gills, head kidney, spleen and muscle when challenged with polyinosinic:polycytidylic acid (poly I:C) or lymphocystis disease virus (LCDV). The up-regulations were stronger and arose earlier in the case of poly I:C treatment in most tested organs in a 7-day time course, with maximum increases ranging from 1.37- to 8.59-fold and peak time points from 3 h to 3 d post injection depending on different organs, relative to those in the case of LCDV treatment which ranged from 1.32- to 3.21-fold and from 18 h to 3 d post injection, respectively. The highest and earliest inductions were detected in the spleen in both challenge cases, while the inductions by LCDV in the muscle were quite faint. These results demonstrate a role of Japanese flounder IRF9 in the host's antiviral responses.
Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China. Electronic address: huguobin@mail.ouc.edu.cn.
Guo-Bin
GB
Hu
College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
Ming-Yu
MY
Zhao
College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
Jing-Yun
JY
Lin
College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
Qiu-Ming
QM
Liu
Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China; College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
Shi-Cui
SC
Zhang
D000704:Analysis of Variance; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D005432:Flounder / Q000235:genetics*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics*; D050834:Interferon-Stimulated Gene Factor 3, gamma Subunit / Q000235:genetics*; D007497:Iridoviridae / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013154:Spleen / Q000378:metabolism; D013997:Time Factors
D017931:DNA Primers; D018076:DNA, Complementary; D050834:Interferon-Stimulated Gene Factor 3, gamma Subunit; D011070:Poly I-C
Antiviral response; Gene expression; IRF9; Molecular structure; Paralichthys olivaceus