草鱼胰岛素样生长因子结合蛋白IGFBP-1基因的全长cDNA克隆及表达

cDNA cloning and expression of insulin-like growth factor binding protein gene IGFBP-1 in Ctenopharyngodon idellus

克隆了草鱼(Ctenopharyngodon idellus)胰岛素样生长因子结合蛋白1(IGFBP-1)基因的全长cDNA,并对草鱼不同时期的胚胎和成鱼不同组织进行了RT-PCR分析,以探索草鱼IGFBP-1基因的生物学功能。结果显示:(1)草鱼IGFBP-1基因cDNA全长为1 135bp,包含一个789 bp阅读框,编码262个氨基酸残基;草鱼与鲤、斑马鱼、沟鲶、大鳞大麻哈鱼、虹鳟、五条、小鼠和人的IGFBP-1氨基酸序列相似度分别为94%、93%、69%、60%、58%、56%、40%和38%;草鱼IGFBP-1蛋白的N端和C端序列负责与胰岛素样生长因子(IGF)结合,其保守性较高。(2)RT-PCR分析结果表明,草鱼胚胎期IGFBP-1 mRNA的表达水平很低,在受精后4 hrs和8 hrs胚胎未能检测到转录本,受精12 hrs后,仅能检测到微量表达;草鱼IGFBP-1mRNA在肝脏、肾脏、肠和心脏组织中具有表达活性。鉴于IGFBP-1基因在IGF信号通路中的重要作用,又是一个低氧诱导基因,上述结果可为进一步探索IGFBP-1基因的功能奠定基础。

In this study, the complete eDNA of a insulin-like growth factor binding gene IGFBP-1 was cloned by rapid amplification of eDNA ends （RACE） in grass carp, Ctenopharyngodon idellus. And mRNA transcripts during embryogenesis and in adult tissues were studied by RT-PCR. The results showed that ： （ 1 ） The complete eDNA of C. idellus IGFBP-1 is 1 135 bp and its ORF includes 789 bp which coding 262 aminoacid residue. The deduced amino acid analysis showed that the sequence similarities between C. idellus and Cyprinus carpio , Danio rerio , lctalurus punctatus , Salmo salar , Oncorhynchus mykiss , Seriola quinqueradiata , Mus musculus and Homo sapiens are 94% , 93% , 69% , 60% , 58% , 56% , 40% and 38% , respectively. Its functional N-terminal and C-terminal domains, which are involved in binding with IGF ligand, are very conservative. （2） RT-PCR results demonstrated that IGFBP-1 gene had a low expression in embryos at different stages in C. idelhts. Weak mRNA transcripts can be detected after 12 hpf. Tissue distribution results showed that IGFBP-1 mRNA was expressed in liver, kidney, intestines and heart. In terms of its crucial function of IGFBP-1 in IGF signal pathway and as a hypoxia-inducible gene, our results provide data for further functional investigations of IGFBP-1 gene in grass carp.