title: Identification, expression and antibacterial activities of an antimicrobial peptide NK-lysin from a marine fish Larimichthys crocea.
abstract: As fundamental immunologic mechanism, the innate immunity system is more important than the specific immunity system in teleost fishes during pathogens infection. Antimicrobial peptides are integral parts of the innate immune system, and play significant roles against pathogens infection. NK-lysin, the compounds of the natural killer cells and cytotoxic T cells, are potent and effective antimicrobial peptides widely distributed in animals. In this study, we reported the sequence characteristics, expression profiles and antibacterial activities of a NK-lysin gene (Lc-NK-lysin) from a commercially important marine fish, the large yellow croaker (Larimichthys crocea). The open reading frame of Lc-NK-lysin cDNA sequence was 447 bp in length, coding 148 amino acids. The genomic DNA of Lc-NK-lysin has the common features of NK-lysin family, consisting of five exons and four introns, and in its deduced mature peptide, there are six well-conserved cysteine residues and a Saposin B domain. Lc-NK-lysin was expressed in all tested tissues (skin, muscle, gill, brain, head kidney, heart, liver, spleen, stomach and intestine) with different expression patterns. In pathogens infection the expression profiles of Lc-NK-lysin varied significantly in gill, head kidney, spleen and liver, indicating its role in immune response. Two peptides (Lc-NK-lysin-1 and Lc-NK-lysin-2) divided from the core region of the Lc-NK-lysin mature polypeptide were chemically synthesized and their antibacterial activities were examined; the potential function on the inhibition of bacteria propagation was revealed. Our results suggested that Lc-NK-lysin is a typical member of the NK-lysin family and as an immune-related gene it involves in the immune response when pathogens invasion.
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, China.
authors.forename: Qi-Jia
authors.initials: QJ
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, China.
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Qiao
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, China.
authors.forename: Wan-Shu
authors.initials: WS
authors.lastname: Hong
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, China. Electronic address: yqsu@xmu.edu.cn.
authors.forename: Yong-Quan
authors.initials: YQ
authors.lastname: Su
authors.affiliation: State Key Laboratory of Breeding of Larimichthys crocea, Ningde 352103, Fujian, China.
authors.forename: Kun-Huang
authors.initials: KH
authors.lastname: Han
authors.affiliation: State Key Laboratory of Breeding of Larimichthys crocea, Ningde 352103, Fujian, China.
authors.forename: Qiao-Zhen
authors.initials: QZ
authors.lastname: Ke
authors.affiliation: State Key Laboratory of Breeding of Larimichthys crocea, Ningde 352103, Fujian, China.
authors.forename: Wei-Qiang
authors.initials: WQ
authors.lastname: Zheng
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001424:Bacterial Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D018407:Bacterial Physiological Phenomena; D001483:Base Sequence; D016798:Ciliophora / Q000502:physiology; D016770:Ciliophora Infections / Q000235:genetics / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005393:Fish Diseases / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000469:parasitology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D010473:Perciformes; D011510:Proteolipids / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary
chemical_list: D023181:Antimicrobial Cationic Peptides; D018076:DNA, Complementary; D029941:Fish Proteins; C093238:NK-lysin; D011510:Proteolipids
keywords: Antibacterial activity; Antimicrobial peptide; Innate immunity; Larimichthys crocea; NK-lysin