甜菊钙调蛋白基因的克隆及结构分析

钙调蛋白（Calmodulin）是生物细胞内一种重要的调控蛋白，通过其与靶酶的相互作用控制细胞正常的生长发育及细胞对外界环境变化的反应，我们从甜菊顶芽和花芽中提取总RNA，逆转录合成cDNA第一链，以此为模板，参考GenBank上已发表植物的钙调蛋白基因序列合成5′端和3′端引物，利用多聚酶链式反应（PCR）扩增并克隆得到了甜菊钙调蛋白基因的两个异型基因，序列分析表明，它们均由450个核苷酸组成，编码148个氨基酸，在核苷酸序列上与迄今已知的多种植物钙调蛋白均有很高的同源性，同源率在83％以上，编码的氨基酸序列同源性更同，同源率高达95％以上，这两个基因之间存在差异，其核苷酸序列同源率为85％，编码区的氨基酸序列的同源率为99％，仅在第122个氨基酸由ALA代替了VAL。

Cloning and Structurl Analysis of Calmodulin Gene from Stevia rebaudiana Bertoni

Calmodulin is a calcium binding protein that modulates the activity of diverse group of proteins including some protein kinase, adenylate cyclases and ATPase. Here we used totle RNA of Stevia rebaudiana Bertoni as the template for PCR. The PCR primers were designed and synthesized according to the 5' ahd 3' terminal oligonucleotide sequences of Calmodulin genes of plants from GenBank.The recombinant clones were obtained on selected medium. The results of DNA sequences analysis show that two calmodulin isoforms of Stevia rebaudiana Bertoni consist of 450 nucletides and encode 148 amino acids. They share more than 83% homologies for nucleotide sequences and 95% for encoding amino acid sequences as compared with those of calmodulin genes of other plants. The two isoform genes share 85% and 99% homologies for nucleotide sequences and encoding amino acid sequences.