花鲈类胰岛素生长因子-1基因的全长cDNA分离与表达分析

Isolation of Full-Length cDNA of Insulin-Like Growth Factor-1(IGF-1)Gene of Japanese Sea Bass(Lateolabrax japonicas)and Its Expression Analysis

采用逆转录聚合酶链式反应(RT-PCR)和cDNA末端快速扩增法(RACE)获得花鲈(Lateolabrax japonicus)类胰岛素生长因子-1(IGF-1)的cDNA全长序列,利用荧光实时定量PCR技术研究了花鲈IGF-1mRNA在成鱼各组织中的表达特征。结果显示,花鲈IGF-1cDNA全长序列为873bp,编码区序列为555bp,编码186个氨基酸,推测成熟氨基酸分为6个结构域,分别是信号肽区域,A、B、C、A、D区域和E肽。花鲈IGF-1氨基酸序列与其他海水鱼类的IGF-1相似度较高,与淡水鱼类相似度较低,与高等脊椎动物相似度更低,说明海水鱼类的IGF-1在进化过程中发生了较大的变化。组织表达分析显示,花鲈IGF-1mRNA在肝脏中表达量最高,在肠、盲肠、肌肉、脾脏中次之;在鳃、垂体、性腺、胃、肾脏、脑、头肾、心脏中表达量较低。本文为鱼类IGF基因功能研究奠定基础,为花鲈生长调控提供科学依据。

The full length cDNA of Lateolabrax japonicus insulin-like growth factor-1 （IGF-1） gene was isolated with RT-PCR and rapid amplification of cDNA ends （RACE）. The cDNA was 873bp in length, which contained an open reading frame （ORF） corresponding to 186 amino acid residules. The deduced mature IGF-1 contained six functional structures： signal peptide, B, C, A and D domain and E peptide. The deduced was highly similar with that of other marine fish species, moderately with that of fresh water fish species and less with that of higher vertebrates, impling that marine fish IGF-1 suffered a manifest change during evolution. The expression analysis of IGF-1 gene with florescent real-time quantitative RT- PCR showed that the abundance of IGF-1 mRNA was the highest in liver, which was followed by the abundance in intestine, cecum, muscle and spleen. The expression of IGF-1 gene was not detectable in gill, pituitary, gonad, stomach, kidney, brain, head kidney and heart.