title: Molecular, genomic, and expressional delineation of a piscidin from rock bream (Oplegnathus fasciatus) with evidence for the potent antimicrobial activities of Of-Pis1 peptide.
abstract: The piscidin family comprises a group of antimicrobial peptides (AMPs) that are vital components of teleost innate immunity. Piscidins protect the host from pathogens, through multifaceted roles as immunomodulators and anti-infective peptides. The present study reports the identification, and characterization of a putative piscidin homolog, Of-Pis1, from rock bream (Oplegnathus fasciatus). A combined genomic and transcriptomic approach revealed that the Of-Pis1 gene comprises 1396 nucleotides (nt), four exons, and three introns. The cDNA with the 213 nt open reading frame encoded a 70-amino acid preprotein consisting of a signal peptide, a mature peptide, and a prodomain. Predicted mature Of-Pis1 was assumed to be a membrane-active AMP, based on the prediction of an amphipathic α-helical conformation with a net charge of +4. In addition, Of-Pis1 demonstrated significant similarities with other piscidin family members in terms of gene structure, sequence homology, and evolutionary relationship. Examination by quantitative real-time PCR (qPCR) of basal transcription of Of-Pis1 in the tissues of naïve rock bream, revealed predominant transcript levels in the gills, followed by the spleen, intestine, skin, and head kidney. In gill tissues, the temporally induced mRNA expression of Of-Pis1, upon in vivo injection trials with lipopolysaccharide (LPS); polyinosinic:polycytidylic acid (poly I:C); and pathogens, including Edwardsiella tarda, Streptococcus iniae, and rock bream iridovirus (RBIV), was weak. In contrast, in vivo flagellin administration led to a robust upregulation of Of-Pis1 in different tissues. Antimicrobial potency was determined by employing recombinant (rOf-Pis1), and synthetic (pOf-Pis1) peptides, in in vitro assays. Recombinant overexpression inhibited the growth of bacteria expressing the rOf-Pis1 protein in a growth delay assay. The broad antimicrobial spectrum of pOf-Pis1 was evidenced by its potent activity against an array of microbes, including bacteria, fungi, and parasitic species. In addition, pOf-Pis1 showed no significant hemolytic toxicity against human erythrocytes. Collectively, the data presented in the current study improve our understanding of the piscidin AMP family, and the contribution of Of-Pis1 to the rock bream immunity.
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 Self-Governing Province 690-756, Republic of Korea.
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 690-756, Republic of Korea.
authors.forename: M S
authors.initials: MS
authors.lastname: Mothishri
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 Self-Governing Province 690-756, Republic of Korea.
authors.forename: William Shanthakumar
authors.initials: WS
authors.lastname: Thulasitha
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 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: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D002176:Candida albicans / Q000187:drug effects / Q000254:growth & development; D002478:Cells, Cultured; D004912:Erythrocytes / Q000187:drug effects; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D016802:Oligohymenophorea / Q000187:drug effects / Q000254:growth & development; D010473:Perciformes / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development; D017422:Sequence Analysis, DNA
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D029941:Fish Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; C449802:moronecidin protein, Morone saxatilis
keywords: Antifungal/antiparasitic activity; Antimicrobial peptide (AMP); Hemolytic cytotoxicity; Innate immune response; Piscidin