绞股蓝鲨烯环氧酶基因的克隆与序列分析

Cloning and Sequence Analysis of Squalene Epoxidase Gene from Gynostemma pentaphyllum

根据已报道植物鲨烯环氧酶（squalene epoxidase,SE）基因cDNA序列的保守区域设计引物,利用RT-PCR和RACE技术,对绞股蓝SE基因进行克隆及序列分析.结果表明,绞股蓝SE基因cDNA全长为1 818 bp,编码一个由525个氨基酸残基组成的多肽.绞股蓝SE基因编码的氨基酸序列中含有52.4%的非极性疏水性氨基酸,26.1%极性中性氨基酸,9.0%酸性氨基酸,12.6%碱性氨基酸.Blast结果显示,绞股蓝SE基因核苷酸序列与其他已报道的植物SE基因相似性为73%～82%,推导的氨基酸序列相似性为63.2%～79.4%.SE氨基酸序列进化分析发现,绞股蓝SE与绿珊瑚、拟南芥亲缘关系较近.

Degenerate primers designed from the conservative domain of squalene epoxidase（SE） in plants were used to amplify the SE fragments from cDNA of Gynostemma pentaphyllum by RT-PCR and RACE technology.The full-length cDNA of SE from G.pentaphyllum had 1 818 bp with an open reading frame encoding 525 amino acids of protein.There are 52.4% of nonpolarity hydrophobic,26.1% of polarity neutral,9.0% of acidic,as well as 12.6% of alkaline amino acid residues in the SE polypeptide chain.The results of homologous analysis in GenBank demonstrated that the sequences had 73%～82% similarity on the nucleotide sequence and 63.2%～79.4% similarity on the deduced amino acid sequence.Furthermore,phylogenic analysis on the amino acid sequence of SE from G.pentaphyllum with those of other plants showed that G.pentaphyllum was closely related to Euphorbia tirucalli and Arabidopsis thaliana.