Department of Bioengineering, Rice University, Houston, TX, USA.
Metab Eng. 2011 Mar;13(2):234-40. doi: 10.1016/j.ymben.2010.11.005. Epub 2010 Dec 7.
The terpenoid indole alkaloid (TIA) pathway in Catharanthus roseus produces two important anticancer drugs, vinblastine and vincristine, in very low yields. This study focuses on overexpressing several key genes in the upper part of the TIA pathway in order to increase flux toward downstream metabolites within hairy root cultures. Specifically, we constructed hairy root lines with inducible overexpression of 1-deoxy-D-xylulose synthase (DXS) or geraniol-10-hydroxylase (G10H). We also constructed hairy root lines with inducible expression of DXS and anthranilate synthase α subunit (ASA) or DXS and G10H. DXS overexpression resulted in a significant increase in ajmalicine by 67%, serpentine by 26% and lochnericine by 49% and a significant decrease in tabersonine by 66% and hörhammericine by 54%. Co-overexpression of DXS and G10H caused a significant increase in ajmalicine by 16%, lochnericine by 31% and tabersonine by 13%. Likewise, DXS and ASA overexpression displayed a significant increase in hörhammericine by 30%, lochnericine by 27% and tabersonine by 34%. These results point to the need for overexpressing multiple genes within the pathway to increase the flux toward vinblastine and vincristine.
长春花中的萜吲哚生物碱（TIA）途径产生两种重要的抗癌药物，长春碱和长春新碱，但其产量非常低。本研究专注于在上游 TIA 途径中过表达几个关键基因，以增加毛状根培养物中下游代谢物的通量。具体来说，我们构建了具有诱导型过表达 1-脱氧-D-木酮糖-5-磷酸合酶（DXS）或香叶醇-10-羟化酶（G10H）的毛状根系。我们还构建了具有诱导型表达 DXS 和邻氨基苯甲酸合酶α亚基（ASA）或 DXS 和 G10H 的毛状根系。DXS 的过表达导致阿马碱增加 67%，蛇根碱增加 26%，洛柯宁碱增加 49%，而-tabersonine 减少 66%，霍赫马琳碱减少 54%。DXS 和 G10H 的共过表达导致阿马碱增加 16%，洛柯宁碱增加 31%，tabersonine 增加 13%。同样，DXS 和 ASA 的过表达导致霍赫马琳碱增加 30%，洛柯宁碱增加 27%，tabersonine 增加 34%。这些结果表明需要在途径中过表达多个基因以增加长春碱和长春新碱的通量。
