title: Cloning, characterization, and expression analysis of a thioredoxin from orange-spotted grouper (Epinephelus coioides).
abstract: Thioredoxins (TRXs) are a family of small, highly conserved proteins that are essential for the maintenance of cellular homeostasis. In this study, a thioredoxin gene was cloned from orange-spotted grouper, Epinephelus coioides (designated as Ec-TRX). The full-length cDNA of Ec-TRX was comprised of 767bp with a 327bp open reading frame that encodes a putative protein of 108 amino acids. Quantitative real-time PCR analysis revealed that the Ec-TRX mRNA was distributed abundantly in grouper, E. coioides skin and liver, and the expression in liver was up-regulated after viral challenge with Singapore grouper iridovirus (SGIV). Recombinant Ec-TRX (rEc-TRX) was expressed in Escherichia coli BL21 (DE3) and purified for mouse anti-Ec-TRX serum preparation. The rEc-TRX fusion protein was demonstrated to possess the expected redox activity in enzymatic analysis, and scavenge free radicals and protect supercoiled DNA from oxidative damage induced by a metal-ion catalyzed oxidation reaction. Subcellular localization revealed that Ec-TRX was distributed in both cytoplasm and nucleus. Overexpression of Ec-TRX in grouper spleen (GS) cells could promote the growth of GS cells and inhibit the replication of SGIV. These results suggest that Ec-TRX could function as an important antioxidant in a physiological context, and perhaps is involved in the responses to viral challenge.
authors.affiliation: Key Laboratory of Marine Bio-resources Sustainable Utilization, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 W. Xingang Rd., Guangzhou, PR China.
authors.forename: Jingguang
authors.initials: J
authors.lastname: Wei
authors.forename: Minglan
authors.initials: M
authors.lastname: Guo
authors.forename: Huasong
authors.initials: H
authors.lastname: Ji
authors.forename: Yang
authors.initials: Y
authors.lastname: Yan
authors.forename: Zhengliang
authors.initials: Z
authors.lastname: Ouyang
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Huang
authors.forename: Youhua
authors.initials: Y
authors.lastname: Hang
authors.forename: Qiwei
authors.initials: Q
authors.lastname: Qin
mesh_terms: D000818:Animals; D001492:Bass / Q000235:genetics; D003001:Cloning, Molecular; D004266:DNA Virus Infections / Q000276:immunology / Q000662:veterinary; D005393:Fish Diseases / Q000276:immunology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D017994:Iridovirus; D010802:Phylogeny; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D029941:Fish Proteins; D013879:Thioredoxins