Role of Bacteria in production of ET-743 in E. turbinata

描述（由申请人提供）：我们的长期目标是：1)研究微生物共生体在海洋天然产物生物合成中的作用，2)开发利用共生体及其生物合成基因的方法，以经济和环境无害的方式生产源自海洋天然产物的药物，3)研究和利用海洋微生物的生物合成途径来生产已知和新颖的结构。海洋无脊椎动物是生物活性代谢物的丰富来源，其中许多是药物开发的优秀候选者。缺乏供应是许多这类化合物开发的最严重障碍之一。在某些情况下，细菌共生体被假设为化合物的真正生物合成来源。ET-743是一种来自海洋海鞘（Ecteinascidia turbinata）的抗癌药物，怀疑是共生来源，目前正在进行II期临床试验。探索ET-743的全部潜力的一个障碍是缺乏供应。已采用水产养殖和半合成两种方法来获得该化合物，但两种方法都不具有成本效益。我们开发了一种生物合成ET-743的方案，基于密切相关的细菌化合物萨弗霉素MX1的非核糖体肽合成酶基因。此外，我们在E. turbinata中发现了一种细菌共生体，可能是ET-743的来源。我们的项目旨在通过培养产生共生体的ET-743和/或克隆生物合成途径的基因来解决供应问题，以实现在异源宿主中表达的长期目标。

DESCRIPTION (provided by applicant): Our long-term objectives are: 1) to investigate the role of microbial symbionts in the biosynthesis of marine natural products, 2) to develop methods to exploit symbionts and their biosynthetic genes for economical and environmentally sound production of drugs derived from marine natural products, and 3) to investigate and exploit biosynthetic pathways of marine microorganisms to produce known and novel structures. Marine invertebrates are rich sources of bioactive metabolites, many of which are excellent candidates for drug development. Lack of supply is one of the most serious barriers to development of many of these compounds. In some cases, bacterial symbionts are hypothesized to be the true biosynthetic source of the compound. ET-743 is an anti-cancer drug from a marine ascidian, Ecteinascidia turbinata, that is suspected to be of symbiotic origin, and which is in Phase II clinical trials. One obstacle to exploring the full potential of ET-743 is lack of supply. Both aquaculture and semi-synthesis have been used to obtain the compound but neither are cost effective. We have developed a biosynthetic scheme for ET-743, based on the nonribosomal peptide synthetase genes for the closely related bacterial compound saframycin MX1 from Myxococcus xanthus. Furthermore, we have identified a bacterial symbiont, the possible source of ET-743, in E. turbinata. Our project aims to solve the supply problem by cultivating the ET-743 producing symbiont and/ or cloning the genes for the biosynthetic pathway to fulfill the long-term goal of expression in a heterologous host. The specific aims are to: 1. Identify, characterize and cultivate the ET-743 producing bacterial symbiont of E. turbinata 2. Identify and clone ET-743 biosynthetic pathway genes.