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

摘要:

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1 135 bp，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。

Abstract:

In this study, the complete cDNA of a insulinlike growth factor binding gene IGFBP-1 was cloned by rapid amplification of cDNA 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 cDNA of C.idellus IGFBP-1 is 1 135 bp and its ORF includes 789 bp which coding 262 aminoacid residue. The deduced amino acid analysis showed that the sequence similarities between C.idellus and Cyprinus carpio, Danio rerio, Ictalurus 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.idellus. 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.