title: Molecular cloning and expression analysis of the liver-expressed antimicrobial peptide 2 (LEAP-2) gene in grass carp.
abstract: Liver-expressed antimicrobial peptide 2 (LEAP-2) is a novel antimicrobial peptide (AMP) recently found in vertebrates, and exhibits distinct amino acid sequence, secondary structure and expression pattern from other peptides. In this study, the LEAP-2 gene and its full-length cDNA were cloned from grass carp. Grass carp LEAP-2 gene consists of two introns and three exons. The translated product contains 92 amino acids, including a 26 amino acids signal peptide and a mature peptide of 41 amino acids. Grass carp LEAP-2 gene was expressed in a wide range of tissues except blood, with the highest level of transcripts found in liver. Upon induction by Aeromonas hydrophila, its expression was significantly up-regulated in liver, gill, skin, muscle, spleen, blood, head kidney, heart and intestine, but down-regulated in trunk kidney and brain. The transcript level was high in embryos at the 16-cell stage but declined gradually afterwards, suggesting that LEAP-2 transcripts in early embryos might be maternal. Mature peptides obtained by in vitro expression displayed selective antimicrobial activities. These results together further our understanding of the physiological function of LEAP-2 in vertebrates.
authors.affiliation: Key Laboratory of Aquatic Genetic Resources and Aquacultural Ecology Certificated by Ministry of Agriculture, Shanghai Ocean University, Shanghai 201306, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Jia-Le
authors.initials: JL
authors.lastname: Li
authors.forename: Gen-Hua
authors.initials: GH
authors.lastname: Yue
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Fu
authors.forename: Zheng-Feng
authors.initials: ZF
authors.lastname: Zhou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D002347:Carps / Q000196:embryology / Q000235:genetics* / Q000276:immunology; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D005260:Female; D029941:Fish Proteins / Q000235:genetics* / Q000276:immunology; D018507:Gene Expression Regulation, Developmental; D007113:Immunity, Innate / Q000235:genetics; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D017386:Sequence Homology, Amino Acid
chemical_list: D023181:Antimicrobial Cationic Peptides; D017931:DNA Primers; D029941:Fish Proteins