中华鳖转铁蛋白基因序列特征及表达研究

MOLECULAR CHARACTERISTICS AND THE EXPRESSION OF TRANSFERRIN GENE IN CHINESE SOFT SHELL TURTLE

  • 摘要: 转铁蛋白是呼吸链的关键因子, 参与体液和免疫系统的调节, 具有抗菌抗病毒等功能。研究从嗜水气单胞菌诱导的中华鳖肝脏SMART cDNA文库中, 分离克隆了中华鳖转铁蛋白基因cDNA和gDNA全序列, 对其序列特征、组织表达及原核表达进行了分析研究。结果显示, 中华鳖转铁蛋白对应全长cDNA的基因组DNA全长为19100 bp, 由17个外显子和16个内含子组成; cDNA全长为2359 bp, 开放阅读框为 2094 bp, 编码697个氨基酸; 转铁蛋白的分子量为76.6 kD, 包含2个糖基化位点, 存在4个二硫键形成区域的缺失, 两个同源结构域的相似性为37%, 信号肽位于第119位点。荧光定量PCR结果显示, 正常组中华鳖转铁蛋白基因在肝脏中的表达量最大; 以嗜水气单胞菌刺激后, 其在心、肝、脾和肾脏组织中的表达, 均有一个上调后减少的趋势。此外, 实验还进行了重组转铁蛋白原核表达和Western blot 检测鉴定, 为深入研究中华鳖转铁蛋白功能的提供了基础数据。

     

    Abstract: Transferrin has a variety of biological functions such as iron transportation, anti-microbial, and immunoregulation. In this study, we isolated the full length cDNA of transferrin of Chinese soft shell turtle (Pelodiscus sinensis) from the constructed liver cDNA library. The cDNA sequence consisted of 2359 bp, including an open reading frame (ORF) of 2094 bp which could encode a 674-aa peptide. The genomic DNA of transferrin consisted of 19100 bp and contained 17 exons and 16 introns, with a structure similar to that of other vertebrates. Using the online software we predicted the molecular characteristics of transferrin. The results indicated that the N-lobe of transferrin had a signal peptide of 19 amino acids; this gene was composed of two similar domains with a similarity of 37%. There were 2 N-linked glycosylation sites in the N-lobe, and 11 disulfide bonding formation areas in amino acids peptide. The quantitative PCR results showed that the expression of transferrin was the highest in liver in the normal group. The results also showed that after the infection with Aeromonas hydrophila the expression of this gene was first increased and then decreased in liver, spleen, kidney and heart, and the increase was particularly high in liver and spleen. Moreover, we applied western-blot to testify the prokaryotic expression of transferrin of Chinese soft shell turtle. This study could provide insights into the biological functions of transferrin in non-specific immune responses.

     

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