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

1066879/1064903 Shanks/Gibson Plants会产生大量化学物质，这些化学物质可用作治疗各种疾病的药物。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，这使得这些药物非常昂贵。这个问题的一个例子是由长春花属产生的一类化合物，称为萜类吲哚生物碱。萜类吲哚生物碱包括用于治疗某些类型癌症的长春新碱和长春花碱等化学物质，以及用于治疗高血压的阿马利辛。由于长春花只生产微量的这些化学物质，它们每磅的价格可能超过100万美元。为了降低这些药物的成本，关键是开发出能够生产更多这些药物的长春花品种。为此，将调查导致这些药物生产的生物合成基因表达增加的影响。为了增加这些生物合成基因的表达，将采取双重战略。这一策略的第一部分是测试减少抑制基因表达的效果，这些基因减少了生物合成基因的表达。这一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，应该可以实现生物合成基因的显著增加。这种生物合成基因表达的增加应该会导致萜类吲哚生物碱产量的增加，从而使那些用作药物的萜类吲哚生物碱能够以较低的成本生产出来。还将分析因生物合成基因表达变化而积累的以前未确定特征的化学物质。对这些化学物质的表征既将提供有关产生萜类吲哚生物碱的生化途径的有价值的信息，也可能提供关于可能被测试用作药物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.