Genomic characterization, expression analysis, and antimicrobial function of a glyrichin homologue from rock bream, Oplegnathus fasciatus

• Published in: Fish & shellfish immunology Vol. 35; no. 5; pp. 1406 - 1415
• Main Authors: Kasthuri, Saranya Revathy, Wan, Qiang, Umasuthan, Navaneethaiyer, Bathige, S D N K, Lim, Bong-Soo, Jung, Hyung-Bok, Lee, Jehee, Whang, Ilson
• Format: Journal Article
• Language: English
• Published: England 01.11.2013
• Subjects: Amino Acid Sequence; Animals; Anti-Infective Agents - metabolism; Anti-Infective Agents - pharmacology; Antimicrobial Cationic Peptides - genetics; Antimicrobial Cationic Peptides - metabolism; Antimicrobial Cationic Peptides - pharmacology; Base Sequence; Cell Membrane - drug effects; Cell Membrane - metabolism; Chromosomes, Artificial, Bacterial; DNA, Complementary - genetics; Edwardsiella tarda - drug effects; Edwardsiella tarda - ultrastructure; Gene Components; Gene Library; Iridoviridae - drug effects; Lipopolysaccharides - metabolism; Liver - metabolism; Microscopy, Electron, Scanning - veterinary; Molecular Sequence Data; Perciformes - genetics; Perciformes - immunology; Phylogeny; Poly I-C - metabolism; Real-Time Polymerase Chain Reaction - veterinary; Reverse Transcriptase Polymerase Chain Reaction - veterinary; Sequence Alignment - veterinary; Sequence Analysis, DNA - veterinary; Streptococcus - drug effects; Streptococcus - ultrastructure; Vaccines, Synthetic - drug effects; Reactive oxygen species modulator 1; Antibacterial activity; Genome characterization; Antiviral activity; Glyrichin
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2013.08.008

Antimicrobial peptides are important innate effector molecules, playing a vital role in antimicrobial immunity in all species. Glyrichin is a transmembrane protein and an antibacterial peptide, exerting its functions against a wide range of pathogenic bacteria. In this study, cDNA and a BAC clone harboring the glyrichin gene were identified from rock bream and characterized. Genomic characterization showed that the OfGlyrichin gene exhibited a 3 exon-2 intron structure. OfGlyrichin is a 79-amino-acid protein with a transmembrane domain at (22)GFMMGFAVGMAAGAMFGTFSCLR(44). Pairwise and multiple sequence alignments showed high identity and conservation with mammalian orthologues. Phylogenetic analysis showed a close relationship with fish species. Higher levels of OfGlyrichin transcripts were detected in the liver from healthy rock bream which were induced by immunogens like lipopolysaccharide, poly I:C, rock bream irido virus, Edwardsiella tarda and Streptococcus iniae. The synthetic peptide (pOf19) showed antibacterial activity against Escherichia coli, E. tarda, and S. iniae. Analysis of the bacterial morphological features after pOf19 peptide treatment showed breakage of the cell membrane, affirming that antibacterial function is accomplished through membrane lysis. The pOf19 peptide also showed antiviral activity against RBIV infection. The high conservation of the genomic structure and protein, together with the antimicrobial roles of OfGlyrichin, provide evidence for the evolutionary existence of this protein playing a vital role in innate immune defense in rock bream.