title: Molecular characterization and functional analysis of a salmon louse (Lepeophtheirus salmonis, Krøyer 1838) heme peroxidase with a potential role in extracellular matrixes.
abstract: Heme peroxidases are the most abundant type of peroxidase catalyzing a H2O2-dependent oxidation of a wide variety of substrates. They are involved in numerous processes like the innate immune response, hormone and prostaglandin synthesis and crosslinking of proteins within extracellular matrixes (ECM) as well as molecules within the cuticle and chorion of arthropods and nematodes. In the present study, a Lepeophtheirus salmonis heme peroxidase (LsHPX) 1 was characterized. Amino acids in the active site of heme peroxidases were conserved, and the predicted protein sequence showed the highest similarity to genes annotated as chorion peroxidases and genes suggested to be involved in cuticle hardening or adhesion. LsHPX1 exhibited a dynamic expression during ontogenesis and during the nauplius molting cycle. Transcripts were localized to muscle cells near the muscle-tendon junction, in nerve tissue especially at neuromuscular junctions, subcuticular epithelium, subepithelial cells facing the hemolymph, exocrine glands within the subepithelial tissue and in isolated cells within the testis. Knock-down of LsHPX1 in nauplius larvae decreased the swimming activity of emerging copepodids. Histological analysis of knock-down animals revealed increased spacing between myofibers and changes in subepithelial and exocrine gland tissue. Considering these results, the potential role of LsHPX1 in crosslinking molecules of salmon louse ECMs is discussed.
authors.affiliation: SLCR-Sea Lice Research Center, Institute of Marine Research, 5817 Bergen, Norway; SLCR-Sea Lice Research Center, Department of Biology, University of Bergen, Thormøhlensgt. 55, 5008 Bergen, Norway. Electronic address: aina-cathrine.overgard@uib.no.
authors.forename: Aina-Cathrine
authors.initials: AC
authors.lastname: Øvergård
authors.affiliation: SLCR-Sea Lice Research Center, Department of Biology, University of Bergen, Thormøhlensgt. 55, 5008 Bergen, Norway.
authors.forename: Christiane
authors.initials: C
authors.lastname: Eichner
authors.affiliation: SLCR-Sea Lice Research Center, Department of Biology, University of Bergen, Thormøhlensgt. 55, 5008 Bergen, Norway.
authors.forename: Frank
authors.initials: F
authors.lastname: Nilsen
authors.affiliation: SLCR-Sea Lice Research Center, Institute of Marine Research, 5817 Bergen, Norway.
authors.forename: Sussie
authors.initials: S
authors.lastname: Dalvin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D017124:Conserved Sequence; D033342:Copepoda / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development / Q000502:physiology; D005109:Extracellular Matrix / Q000201:enzymology / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D006418:Heme / Q000378:metabolism*; D008018:Life Cycle Stages; D008297:Male; D018978:Molting; D009469:Neuromuscular Junction / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D009928:Organ Specificity; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010544:Peroxidases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D013379:Substrate Specificity; D013550:Swimming
chemical_list: D060829:Arthropod Proteins; D006418:Heme; D010544:Peroxidases
keywords: Arthropod; Copepod; Development; Hemocoel; Hemolymph; Muscle; Neuromuscular junction; RNA interference; ROS