title: Comparative analysis of two thioredoxin-like genes in black rockfish Sebastes schlegelii and their possible involvement in redox homeostasis and innate immune responses.
abstract: Elevated levels of ROS can cause serious intracellular damages by reacting readily with nucleic acids, proteins and lipids, thus triggering tissue damage and cell death. Thioredoxin system is one of the principal factors that maintain the intracellular redox balance via its antioxidant property. In this study, we characterized two new thioredoxin isoforms (SsTXN-like 1 and SsMtTXN-like) from black rockfish, Sebastes schlegelii. The molecular and structural characteristics, as well as the evolutionary relationships of SsTXN-like 1 and SsMtTXN-like confirmed that they belong to the thioredoxin superfamily. A classical thioredoxin domain was found in both proteins with a conserved redox-active site CXYC, however, only the precursor of SsMtTXN-like protein possessed a mitochondrial targeting signal. The results from insulin disulfide reduction activity assay demonstrated that their recombinant proteins are capable of reducing the disulfide bonds of oxidatively damaged proteins via their oxidoreductase activities. The free radical scavenging activity assay revealed the prominent hydroxyl and DPPH scavenging activities of rSsTXN-like 1 and rSsMtTXN-like in a dose-dependent manner. Transcriptional studies showed a broad distribution of SsTXN-like 1 and SsMtTXN-like transcripts in all the examined tissues. Significant (p < 0.05) up-regulations of both genes in immune-related tissues after LPS, poly I:C and Streptococcus iniae challenges reflect their critical role in redox homeostasis in black rockfish. Taken together, SsTXN-like 1 and SsMtTXN-like, as two active members of thioredoxin superfamily, have significant antioxidant properties to housekeep the redox potential during various stress conditions and innate immune response of Sebastes schlegelii.
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea.
authors.forename: Roopasingam
authors.initials: R
authors.lastname: Kugapreethan
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea; Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-8570, Japan.
authors.forename: Navaneethaiyer
authors.initials: N
authors.lastname: Umasuthan
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wan
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea.
authors.forename: William Shanthakumar
authors.initials: WS
authors.lastname: Thulasitha
authors.affiliation: Informatics Development & Management Group, Korea Institute of Oriental Medicine, 1672 Yuseongdae-ro, Yuseong-gu, Daejeon 34054, Republic of Korea. Electronic address: chulnice@kiom.re.kr.
authors.forename: Chul
authors.initials: C
authors.lastname: Kim
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province 63243, Republic of Korea. Electronic address: jehee@jejunu.ac.kr.
authors.forename: Jehee
authors.initials: J
authors.lastname: Lee
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D005075:Biological Evolution; D017124:Conserved Sequence / Q000235:genetics; D005393:Fish Diseases / Q000276:immunology*; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D016166:Free Radical Scavengers / Q000378:metabolism*; D006706:Homeostasis; D007113:Immunity, Innate; D010084:Oxidation-Reduction; D010473:Perciformes / Q000276:immunology*; D000072417:Protein Domains / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics; D013290:Streptococcal Infections / Q000276:immunology*; D000070058:Streptococcus iniae / Q000276:immunology*; D040681:Structural Homology, Protein; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D029941:Fish Proteins; D016166:Free Radical Scavengers; D020033:Protein Isoforms; D013879:Thioredoxins
keywords: Antioxidant; Black rockfish; Radical scavenging activity; Reactive oxygen species (ROS); Thioredoxin (TXN)