Gu Wei, Wu Qi-nan, Chao Jian-guo, Xi Bei-li, Li Lin, Shen Xiu-yuan
College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210046, China.
Yao Xue Xue Bao. 2011 May;46(5):605-12.
Triterpenes, which have large application potential in the treatment of cancer, are the main active components of genuine medicinal material Alisma orientale (Sam.) Juzep. Farnesyl pyrophosphate synthase (FPPS) is one of the important rate-limiting enzymes in the synthetic pathway of triterpenes. In this study the FPPS full length cDNA of the A. orientale, was cloned via homology-based cloning approach and rapid amplification of cDNA ends (RACE). The full length of the FPPS cDNA was 1 531 bp (accession no. HQ724508), which contained a full 1 032 bp ORF that encoded 343 amino acids. The deduced protein sequence exhibited five conserved motifs, two of which is riched of Asp (DDXXD). The result of real-time quantitative PCR (QRT-PCR) showed that FPPS gene was expressed in different organs of A. orientale. The expression increased from October to the first ten-day period of December, and then decreased. The FPPS gene expression was higher in leaves but lower in leafstalk, tuber and root. HPLC analysis of active components 23-acetyl-alismol B of A. orientale. during different periods indicated that its change trend should be consistent with FPPS gene expression. It can be primarily deduced that FPPS gene should be an important control point in the synthetic pathway of Alisma terpenes. This study may facilitate the quality of medicinal plants through gene engineering in the future.
三萜类化合物是正品药材泽泻[Alisma orientale (Sam.) Juzep.]的主要活性成分,在癌症治疗方面具有巨大的应用潜力。法尼基焦磷酸合酶(FPPS)是三萜类化合物合成途径中的重要限速酶之一。本研究通过同源克隆法和cDNA末端快速扩增技术(RACE)克隆了泽泻的FPPS全长cDNA。FPPS cDNA全长1 531 bp(登录号:HQ724508),包含一个1 032 bp的完整开放阅读框,编码343个氨基酸。推导的蛋白质序列具有5个保守基序,其中2个富含天冬氨酸(DDXXD)。实时定量PCR(QRT-PCR)结果表明,FPPS基因在泽泻的不同器官中均有表达。其表达量从10月至12月上旬升高,随后降低。FPPS基因在叶片中表达量较高,而在叶柄、块茎和根中表达量较低。对泽泻不同时期活性成分23-乙酰泽泻醇B的HPLC分析表明,其变化趋势应与FPPS基因表达一致。初步推断,FPPS基因应是泽泻萜类化合物合成途径中的一个重要控制点。本研究可能为今后通过基因工程提高药用植物质量提供帮助。