title: Molecular cloning and expression analysis of two β-defensin genes in the blunt snout bream (Megalobrama amblycephala).
abstract: β-Defensins are a group of cysteine-rich, cationic antimicrobial peptides that play important roles in innate immune system against pathogenic microbes invading. In this study, the part-length cDNA sequences of two β-defensin genes (maΒD-1, maΒD-2) in blunt snout bream (Megalobrama amblycephala) were identified. Homology analysis showed that the cDNA sequences of maΒD-1 and maΒD-2 had high similarities to those in common carp and zebrafish. Real-time quantitative PCR results exhibited that expression level of maΒD-1 in juvenile tissues was the highest in skin, followed by blood and liver, whereas maΒD-2 was lowly expressed in liver, kidney, brain and foregut. In the early development period, fertilized eggs to 31-day post-hatching (dph) larvae, the expression levels of maΒD-1 were higher at the stage from heart beat stage to 3 dph with the highest value at 1 dph, whereas maΒD-2 was expressed higher at fertilized eggs and late cleavage stages. Following bacterial stimulation in vivo by Aeromonas sobria, maΒD-2 expressions were significantly up-regulated in liver, skin, gill, and foregut of juveniles, and maΒD-1 expressions were significantly up-regulated in liver and skin. The results suggest that maΒD-1 and maΒD-2 may play important roles in protecting blunt snout bream embryos, fry and juveniles from pathogenic microbe invading.
authors.affiliation: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Liang
authors.forename: Dan-Dan
authors.initials: DD
authors.lastname: Wang
authors.forename: Gui-Rong
authors.initials: GR
authors.lastname: Zhang
authors.forename: Kai-Jian
authors.initials: KJ
authors.lastname: Wei
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Wang
authors.forename: Gui-Wei
authors.initials: GW
authors.lastname: Zou
mesh_terms: D000333:Aeromonas / Q000276:immunology / Q000472:pathogenicity; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003530:Cyprinidae / Q000235:genetics* / Q000382:microbiology; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation; D010802:Phylogeny; D014018:Tissue Distribution; D015027:Zebrafish / Q000235:genetics; D023083:beta-Defensins / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology
chemical_list: D018076:DNA, Complementary; D023083:beta-Defensins
keywords: Antimicrobial peptide; Bacterial stimulation; Gene expression; Megalobrama amblycephala; β-Defensins