Collaborative research: metabolic engineering of terpenoid indole alkaloids using transcriptional regulators in C. roseus hairy roots

植物产生大量的化学物质，这些化学物质可作为药物用于治疗各种疾病。不幸的是，这些化学物质通常是由植物产生的，只有微量的。因此，必须经常使用大量的植物材料来生产少量的药物，使这些药物非常昂贵。这一问题的一个例子是长春花（Catharanthus roseus，长春花）产生的一类化合物，称为萜类吲哚生物碱。萜类吲哚生物碱包括一些化学物质，如长春新碱和长春花碱，它们被用来治疗某些类型的癌症，而杨柳碱被用来治疗高血压。由于长春花只产生微量的这些化学物质，每磅它们的价格可能超过100万美元。为了降低这些药物的成本，开发能产生更多这些药物的长春花品种是至关重要的。为此目的，将研究增加负责生产这些药物的生物合成基因的表达的影响。增加这些生物合成基因表达的双重策略将被追求。该策略的第一部分是测试减少抑制基因表达的效果，抑制基因会降低生物合成基因的表达。该策略的第二部分是减少抑制基因的表达，同时增加激活基因的表达，从而增加生物合成基因的表达。正在测试的假设是，通过减少抑制因子的表达和增加激活因子的表达，应该有可能实现生物合成基因表达的显著增加。这种生物合成基因表达的增加将导致萜类吲哚生物碱的产量增加，从而使那些可用作药物的萜类吲哚生物碱能够以较低的成本生产。在生物合成基因表达变化的反应中积累的先前未表征的化学物质也将被分析。这些化学物质的特性将提供有关萜类吲哚生物碱产生的生化途径的宝贵信息，并可能提供有关可作为药物使用的其他化学物质的信息。

1066879/1064903 Shanks/GibsonPlants produce large numbers of chemicals that are useful as drugs for treating a variety of medical conditions. Unfortunately, these chemicals are often produced by plants in only trace amounts. As a result, large quantities of plant material must often be used to produce small amounts of drugs, making these drugs very expensive. An example of this problem is provided by a class of compounds produced by Catharanthus roseus (periwinkle), known as terpenoid indole alkaloids. Terpenoid indole alkaloids include chemicals such as vincristine and vinblastine, which are used to treat certain types of cancer, and ajmalicine, which is used to treat hypertension. As periwinkle produces these chemicals in only trace amounts, they can cost over one million dollars per pound. To reduce the costs of these drugs, it is critical to develop varieties of periwinkle that produce these drugs in higher amounts. Towards that end, the effects of increasing expression of the biosynthetic genes that are responsible for production of these drugs will be investigated. A two-fold strategy for increasing expression of these biosynthetic genes will be pursued. Part one of this strategy is to test the effects of reducing expression of repressor genes that decrease expression of the biosynthetic genes. Part two of this strategy is to decrease expression of the repressor genes while simultaneously increasing expression of activator genes that increase expression of the biosynthetic genes. The hypothesis being tested is that, by decreasing expression of repressors and increasing expression of activators, it should be possible to achieve a significant increase in expression of the biosynthetic genes. This increase in expression of the biosynthetic genes should then lead to increased production of terpenoid indole alkaloids, allowing those terpenoid indole alkaloids that are useful as drugs to be produced at a lower cost. Previously uncharacterized chemicals that accumulate in response to alterations in expression of the biosynthetic genes will also be analyzed. Characterization of these chemicals will both provide valuable information regarding the biochemical pathways by which terpenoid indole alkaloids are produced, as well as potentially providing information regarding additional chemicals that may be tested for use as drugs.