Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10972024 | Fish & Shellfish Immunology | 2014 | 12 Pages |
Abstract
The interferon regulatory factor 5 (IRF5) is a key mediator of the Toll-like receptor (TLR)7 and TLR8 signaling pathways. In this study, we describe the identification of IRF5 (Rb-IRF5) from rock bream fish (Oplegnathus fasciatus) and its characteristics features at the genomic and expression levels. The full-length Rb-IRF5 sequence was identified from a cDNA library and its genomic sequence was obtained by screening and sequencing of a bacterial artificial chromosome (BAC) genomic DNA library of rock bream. The genomic sequence is comprised of 8 exons interrupted by 7 introns. The complete coding sequence of Rb-IRF5 is 1497 bp in length and encodes for 498 amino acids. The putative Rb-IRF5 protein consists of 3 important conserved domains: a DNA-binding domain (DBD) at the N-terminus, an IRF-associated domain (IAD), and a virus-activated domain (VAD) at the C-terminus. Based on pairwise sequence analysis, the highest sequence similarity/identity for Rb-IRF5 was observed with the IRF5 gene from turbot fish (>87%) and Japanese flounder (83%). Several important putative transcription factor-binding sites shared by the IRF gene family, including the NF-κB, Ap-1, IRF-1, and ICSBP/ISRE sites, were found in the 5Ⲡflanking region of Rb-IRF5. The predicted tertiary structure of the dimerized IAD and VAD of the Rb-IRF5 protein resembled that of its orthologs from humans. In healthy rock bream, the highest constitutive expression of Rb-IRF5 was detected in the liver. After iridovirus and polyinosinic-polycytidylic acid (poly(I:C)) challenge, Rb-IRF5 expression was significantly induced in the head kidney. Furthermore, rock bream recombinant type I interferon (Rb-IFN1) was also found to be an efficient inducer of Rb-IRF5 in a head kidney primary cell culture model. Upon IRF5 transfection, rock bream Mx (Rb-Mx), interferon I (Rb-IFN1) and tumor-necrosis factor α (Rb-TNFα) genes get significantly upregulated in rock bream heart cells. The findings of the present study explain the involvement of Rb-IRF5 in the induction of interferons and pro-inflammatory cytokines and thereby provide a model for how IRF5 modulates immune responses against viral infections in rock bream.
Keywords
Related Topics
Life Sciences
Agricultural and Biological Sciences
Aquatic Science
Authors
W.D. Niroshana Wickramaarachchi, Qiang Wan, Bong-Soo Lim, Hyung-Bok Jung, Mahanama De Zoysa, Myoung-Ae Park, Jehee Lee, Ilson Whang,