Characterization of c-Jun from orange-spotted grouper, Epinephelus coioides involved in SGIV infection. Issue 1 (March 2015)

• Record Type: Journal Article
• Authors: Wei, Shina; Huang, Youhua; Huang, Xiaohong; Qin, Qiwei
• Is Part Of: Fish & shellfish immunology. Volume 43:Issue 1(2015:Mar.)
• Page Start: 230
• Page End: 240
• Publication Date: 2015-03
• Subjects: Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2014.12.033
• Languages: English
• ISSNs: 1050-4648

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Abstract</title> <sec> <p id="abspara0010">The nuclear phosphoprotein c-Jun is a member of the AP1 family of transcription activating complex, can be induced by various extracellular stimuli such as virus infection. In this study, the c-Jun gene (Ec-c-Jun) was cloned from orange-spotted grouper, <italic>Epinephelus coioides</italic>. The full-length Ec-c-Jun cDNA is composed of 2046 bp and encodes a polypeptide of 328 amino acids with 81% identity of zebrafish. Amino acid alignment analysis indicated that Ec-c-Jun contained three conserved domains including a transactivation domain (TAD), a DNA-binding domain (DBD) and leucine zipper domain (LZD). RT-PCR results showed that Ec-c-Jun transcript was most abundant in spleen, kidney, heart and gill. The expression of Ec-c-Jun was up-regulated after challenged with Singapore grouper iridovirus (SGIV). To investigate the roles of Ec-c-Jun during SGIV infection, we constructed its dominant-negative mutant (DN-Ec-c-Jun) by deleting the major TAD that lacks amino acids 3–122. Fluorescence microscopy observation revealed that Ec-c-Jun and DN-Ec-c-Jun were expressed predominantly in the nucleus in transfected cells. Interestingly, the green fluorescence of Ec-c-Jun was congregated and co-localized with virus assembly sites at the late stage of SGIV infection. However, in DN-Ec-c-Jun transfected cells, no virus assembly sites were observed, and the distribution of fluorescence remained unchanged. Moreover, overexpression of DN-Ec-c-Jun in <italic>vitro</italic> delayed the occurrence of CPE induced by SGIV infection and inhibited the virus gene transcription. In addition, ectopic expression of DN-Ec-c-Jun was able to inhibit SGIV induced c-Jun/AP1 promoter activity in GS cells. Thus, we proposed that c-Jun transcription factor was essential for SGIV replication <italic>in vitro</italic>. Our results will contribute to understanding the crucial roles of JNK signaling pathway in fish virus infection.</p> </sec> </abstract>