title: A teleostan homolog of catalase from black rockfish (Sebastes schlegelii): insights into functional roles in host antioxidant defense and expressional responses to septic conditions.
abstract: Antioxidative defense renders a significant protection against environmental stress in organisms and maintains the correct redox balance in cells, thereby supporting proper immune function. Catalase is an indispensable antioxidant in organisms that detoxifies hydrogen peroxides produced in cellular environments. In this study, we sought to molecularly characterize a homolog of catalase (RfCat), identified from black rockfish (Sebastes schlegelii). RfCat consists of a 1581 bp coding region for a protein of 527 amino acids, with a predicted molecular weight of 60 kD. The protein sequence of RfCat harbored similar domain architecture to known catalases, containing a proximal active site signature and proximal heme ligand signature, and further sharing prominent homology with its teleostan counterparts. As affirmed by multiple sequence alignments, most of the functionally important residues were well conserved in RfCat. Furthermore, our phylogenetic analysis indicates its common vertebrate ancestral origin and a close evolutionary relationship with teleostan catalases. Recombinantly expressed RfCat demonstrated prominent peroxidase activity that varied with different substrate and protein concentrations, and protected against DNA damage. RfCat mRNA was ubiquitously expressed among different tissues examined, as detected by qPCR. In addition, RfCat mRNA expression was modulated in response to pathogenic stress elicited by Streptococcus iniae and poly I:C in blood and spleen tissues. Collectively, our findings indicate that RfCat may play an indispensable role in host response to oxidative stress and maintain a correct redox balance after a pathogen invasion.
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Don Anushka Sandaruwan
authors.initials: DA
authors.lastname: Elvitigala
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Thanthrige Thiunuwan
authors.initials: TT
authors.lastname: Priyathilaka
authors.affiliation: Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Ilson
authors.initials: I
authors.lastname: Whang
authors.affiliation: Biotechnology Research Division, National Fisheries Research and Development Institute, 408-1 Sirang-ri, Gijang-up, Gijang-gun, Busan 619-705, Republic of Korea.
authors.forename: Bo-Hye
authors.initials: BH
authors.lastname: Nam
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Self-Governing Province 690-756, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea. Electronic address: jehee@jejunu.ac.kr.
authors.forename: Jehee
authors.initials: J
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002374:Catalase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004249:DNA Damage; D018076:DNA, Complementary / Q000235:genetics; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D058619:Maltose-Binding Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010473:Perciformes / Q000235:genetics*; D009195:Peroxidase / Q000378:metabolism; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018805:Sepsis / Q000378:metabolism*; D016415:Sequence Alignment; D013154:Spleen / Q000378:metabolism; D013291:Streptococcus
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D058619:Maltose-Binding Proteins; D011993:Recombinant Fusion Proteins; D002374:Catalase; D009195:Peroxidase; D011070:Poly I-C
keywords: Antioxidant properties; Black rockfish; Catalases; Immune challenge; Transcriptional analysis