title: Identification, expression and bioactivity of Paramisgurnus dabryanus β-defensin that might be involved in immune defense against bacterial infection.
abstract: β-defensins are a large family of multi-disulfide-bonded peptides with broad-spectrum antimicrobial activities that contribute to innate host defense in many organisms, but little information is available about β-defensins produced by freshwater fish lacking scales. We therefore cloned and identified a β-defensin gene from Chinese loach (Paramisgurnus dabryanus) by designing degenerate primers and using thermal asymmetric interlaced PCR. This gene is the first defensin gene ever identified in a non-scaled freshwater fish. Annotation of the protein domain architecture showed that the putative Chinese loach β-defensin contains the signature motif of six conserved cysteines within the mature peptide, an aspect similar to β-defensins of other marine fish. We also used quantitative real-time PCR to investigate the expression pattern of the Chinese loach β-defensin gene, mRNA of which could be observed in various tissues. After challenge with the pathogenic bacterium Aeromonas hydrophila, β-defensin expression was induced in the eye, gill, skin, and spleen of the adult loach. The bioactivity of the recombinant P. dabryanus β-defensin was examined against pathogenic bacteria, and the results suggest that this class 2 β-defensin has potential applications for treatment of bacterial infections.
authors.affiliation: Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing 100081, PR China.
authors.forename: Yeyu
authors.initials: Y
authors.lastname: Chen
authors.forename: Heng
authors.initials: H
authors.lastname: Zhao
authors.forename: Xinshang
authors.initials: X
authors.lastname: Zhang
authors.forename: Huiying
authors.initials: H
authors.lastname: Luo
authors.forename: Xianli
authors.initials: X
authors.lastname: Xue
authors.forename: Zhongyuan
authors.initials: Z
authors.lastname: Li
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D003531:Cypriniformes / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007113:Immunity, Innate; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary; D023083:beta-Defensins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D023083:beta-Defensins
keywords: Anti-bacterial activity; Inducible expression; Paramisgurnus dabryanus; β-Defensin