茶树硒营养代谢关键酶硒半胱氨酸甲基转移酶基因克隆及启动子结构分析

为探明茶树硒营养代谢关键酶基因硒半胱氨酸甲基转移酶（SMT，GenBank登录号： DQ480337）的表达调控规律，通过PCR和基因步移技术获得SMT的DNA全长和部分启动子序列，用PLACE、PlantCARE分析SMT内含子和启动子的序列，预测其顺式作用元件及功能。结果表明SMT基因全长5473bp，有7个外显子和6个内含子，内含子富含光响应元件，激素响应元件和抗逆性相关元件，通过基因步移法克隆得到的SMT启动子长375bp，除了含核心启动子保守元件TATA-box和CAAT-obx外，还有其它重要顺式作用元件，如光响应元件、低温响应元件和胚乳表达特异性元件等。植物硒营养代谢关键酶SMT启动子的克隆及结构分析为进一步揭示SMT基因的生物学功能和表达调控机制奠定了理论基础。

The DNA cloning about SMT the key enzyme related to selenium metabolism and the structure analysis of its promoter

In order to explore the regulation and control of gene expression about selenocysteine methyltransferase (SMT) the key enzyme related to selenium metabolism, the full-length DNA sequence and part promoter sequence of SMT were obtained using the technology of PCR and gene walking. The intron and promoter of SMT were analyzed by the tools of PLACE and PlantCARE to predicte its cis-acting element and function. The result showed that the full-length of SMT was 5473bp which contained 7 exons and 6 introns. The introns riched in light responsive elements, Hormone response element and resistance associated element. The promoter of SMT got by the method of genome walking was 375bp. In addition to the core promoter conserved elements of TATA-box and CAAT-box, there are many other important cis-acting elements as light response elements, low temperature response elements and endosperm specific expression elements and so on. The promoter cloning and structural analysis of key enzyme SMT gene related to selenium nutrition metabolism provided a theoretical basis for further revealing the biological function and regulation mechanism of SMT gene expression.