人转铁蛋白基因的克隆及序列分析

目的:克隆人转铁蛋白基因并对其编码序列进行分析.方法:以人胎肝cDNA为模板,利用PCR方法克隆人转铁蛋白基因;通过与基因组序列对比分析基因组结构;通过TargetP 1.1和SignalP 3.0预测信号肽;通过Clustal X(1.81)进行蛋白序列联配.结果:PCR扩增了一个长2 160 bp的基因片断,序列分析表明其覆盖了完整编码框,编码由698个氨基酸组成的人转铁蛋白.进一步分析发现人转铁蛋白基因有19个外显子和18个内含子,编码人转铁蛋白N端具有19个氨基酸组成的信号肽序列.人转铁蛋白与猩猩、猴子、兔子和老鼠的转铁蛋白氨基酸相似率分别为94%、91%、78%、73%.生物信息分析表明,人转铁蛋白含有高度保守的参与蛋白二硫键形成的半胱氨酸以及铁离子结合位点,有两个序列较同源的结构域.结论:成功克隆人转铁蛋白基因,人转铁蛋白与其它物种转铁蛋白同源.

Cloning and sequence analysis of human transferrin gene

Aim:To clone the human transferrin gene and analyze its coding sequence. Methods: PCR was employed to clone the human transferrin gene using human fetal liver cDNA as template.Genomic structure was analyzed by comparing it with human genomic sequence.Signal peptide was predicted by TargetP 1.1 and SignalP 3.0 and Clustal X(1.81) was used for alignment.Results: A DNA fragment of 2 160 bp was cloned and sequencing analysis indicated that it carried an entire open reading frame and encoded a protein of 698 amino acid residues.It contained 19 exons and 18 introns and a signal peptide of 19 residues was predicted.The deduced amino acid sequence of human transferrin showed similarities of 94%,91%,78% and 73% with those from Pongo pygmaeus,Macaca fascicularis,Oryctolagus cuniculus and Rattus norvegicus.Highly conserved regions of the Fe binding sites and cysteine positions which should involved in constitution of secondary structure were found in human transferrin.Bioinformatical analysis indicated that human transferrin was composed of two homologous domains.Conclusion:The human transferrin gene was cloned successfully and human transferrin was homologous with transferrin from other species.