尼罗罗非鱼Hepcidin基因结构与序列分析

Hepcidins是一类具有调节铁代谢功能的抗菌肽.利用RT-PCR、RACE和LA等技术,以尼罗罗非鱼Oreochro-mis niloticus(Linnaens)]肝脏中分离和克隆到Hepcidin基因.其全长cDNA为505 bp(不包括polyA),5′端非翻译区有85 bp,3′非编码区为156 bp,阅读框为264 bp.其编码的氨基酸包括信号肽和前体肽等,前体肽进一步酶解产生22个氨基酸的活性肽,该活性肽具有Hepcidin基因家族特有8个半胱氨酸的保守序列.罗非鱼的Hepcidin基因结构包含3个外显子和2个内含子.本研究为今后阐明Hepcidin基因表达特性、表达产物理化性质、抗菌活性及其相关功能等奠定基础.

Cloning, Sequence Analysis and Gene Organization of Antimicrobial Peptide Hepcidin Gene from Nile Tilapia(Oreochromis niloticus)

Antimicrobial peptides are important components of the host innate immune response against microbial invasion.Hepcidin is an antimicrobial peptide and iron regulatory molecule primarily expressed in liver,and conserved among vertebrates.To date,there are several species of fish Hepcidins that have been isolated and characterized.It was speculated that Hepcidin might be widely spread among fish.In the study,one homologous Hepcidin gene was amplified from the liver of another commercially cultured fish(Oreochromis niloticus) by RT-PCR and RACE method.The complete Hepcidin cDNA is 505 bp(excluding poly A) and the Open Reading Frame(ORF) of 264 bp encoding a peptide of 87 amino acids.The prepro-peptide contains a putative 24-residue signal peptide and a pro-peptide of 63 amino acids,the latter may be further processed into a 22-residues mature peptide.The deduced amino acid sequence and gene organization were highly conserved between tilapia and other organisms,which share eight cysteines at the identical conserved position and consist of two introns and three exons.