Molecular cloning and expression analysis of liver-expressed antimicrobial peptide 1 (LEAP-1) and LEAP-2 genes in the blunt snout bream (Megalobrama amblycephala)

• Published in: Fish & shellfish immunology 2013-08, Vol.35 (2), p.553-563
• Main Authors: Liang, Tao, Ji, Wei, Zhang, Gui-Rong, Wei, Kai-Jian, Feng, Ke, Wang, Wei-Min, Zou, Gui-Wei
• Format: Article
• Language: English
• Subjects: Aeromonas hydrophila - physiology; Amino Acid Sequence; Animals; Antimicrobial peptide; Base Sequence; Cloning, Molecular; Cyprinidae - genetics; Cyprinidae - growth & development; Cyprinidae - immunology; Cyprinidae - metabolism; DNA, Complementary - genetics; DNA, Complementary - metabolism; Embryo, Nonmammalian - embryology; Embryo, Nonmammalian - immunology; Embryo, Nonmammalian - metabolism; Fish Proteins - chemistry; Fish Proteins - genetics; Fish Proteins - metabolism; Gene expression; Hepcidins - chemistry; Hepcidins - genetics; Hepcidins - metabolism; Larva - growth & development; Larva - immunology; Larva - metabolism; LEAP-1; LEAP-2; Megalobrama amblycephala; Molecular Sequence Data; Organ Specificity; Phylogeny; Real-Time Polymerase Chain Reaction - veterinary; RNA, Messenger - genetics; RNA, Messenger - metabolism; Sequence Alignment - veterinary
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2013.05.021

Liver-expressed antimicrobial peptide 1 (LEAP-1) and LEAP-2 are widespread in fish and extremely important components of the host innate immune system. In this study, full-length cDNAs of LEAP-1 and LEAP-2 were cloned and sequenced from blunt snout bream, Megalobrama amblycephala. The open reading frames (ORF) of LEAP-1 and LEAP-2 genes encode putative peptides of 94 and 92 amino acids, which possess eight and four conserved cysteine residues, respectively. The homologous identities of deduced amino acid sequences show that the LEAP-1 and LEAP-2 of blunt snout bream share considerable similarity with those of grass carp. The mRNA expressions of LEAP-1 and LEAP-2 were detectable at different early developmental stages of blunt snout bream and varied with embryonic and larval growth. LEAP-1 and LEAP-2 were expressed in a wide range of adult tissues, with the highest expression levels in the liver and midgut, respectively. Bacterial challenge experiments showed that the levels of LEAP-1 and LEAP-2 mRNA expression were up-regulated in the liver, spleen, gill and brain of juvenile blunt snout bream. These results indicate that the LEAP-1 and LEAP-2 may play important roles in early development of embryos and fry, and may contribute to the defense against the pathogenic bacterial invasion. This study will further our understanding of the function of LEAP-1 and LEAP-2 and the molecular mechanism of innate immunity in teleosts. •Full-length cDNAs of LEAP-1 and LEAP-2 were cloned in blunt snout bream.•Deduced amino acid sequences of LEAP-1 and LEAP-2 were analyzed.•Expression levels of two genes were up-regulated in early embryonic stages and fry.•Two genes were expressed in various tissues with different expression profiles.•Two genes' expressions were up-regulated in four tissues after bacterial challenge.