基于球孢链霉菌C-1027基因组信息发掘新型天然产物

Streptomyces globisporus C-1027, isolated from a soil sample collected in the Qian-jiang area of China, produces an extremely potent antitumor antibiotic, lidamycin. As a member of enediyne family, lidamycin is currently undergoing phase II clinical trial in China and will be expected to become a new drug with independent intellectual property rights. Draft genome sequence of S. globisporus C-1027 suggested that there are a large number of putative gene clusters of secondary metabolites in the genome and most of them appear to be completely novel. In this project, we will uncover new natural products based on the method of genome mining of their biosynthetic gene clusters. The fine map of genome will reveal some new biosynthetic genes of natural product and the putative structure type of natural products could be deduced by analyzing functions and organization of their biosynthetic gene. The putative gene clusters will be subjected to functional analysis by gene disruption, complemention and overexpression. Furthermore, some silent biosynthetic gene clusters will be expressed in heterologous model Streptomyces. The study of the putative gene clusters will disclose biosynthetic pathways of new natural products and provide more biosynthetic elements, which will lay the foundation for the development of novel microbial drugs using synthetic biologic techniques.

球孢链霉菌C-1027分离自湖北潜江土壤中，能产生新型抗肿瘤抗生素力达霉素，具有我国自主知识产权。力达霉素的生物合成途径和调控机制已初步阐明。基因组草图分析显示该菌株基因组中含有非常丰富的天然产物生物合成基因资源。本项目拟采用基因组发掘方法，在球孢链霉菌基因组中寻找新天然产物的生物合成基因簇，从而发现新的活性化合物。通过全基因组精细测序，发现可能的天然产物生物合成基因簇；根据其中关键基因的结构及组成，推测天然产物的化学结构和类型；通过阻断关键基因，确定基因簇与发酵产物中活性化合物的对应关系；敲除或过表达可能的转录因子，诱导"隐形生物合成基因簇"的激活，或将"隐形生物合成基因簇"导入遗传背景清晰的模式链霉菌中进行异源表达，尝试获得新天然产物。将基因组发掘策略应用于寻找球孢链霉菌新型天然产物，将揭示更多新型活性产物生物合成元件以及合成途径，为利用合成生物学技术进行创新微生物药物的研发奠定基础。

球孢链霉菌C-1027分离自湖北潜江土壤中，能产生新型抗肿瘤抗生素力达霉素，具有我国自主知识产权。力达霉素的生物合成途径和调控机制已初步阐明。基因组草图分析显示该菌株基因组中含有非常丰富的天然产物生物合成基因资源。本项目采用基因组发掘方法，在球孢链霉菌基因组中寻找新天然产物的生物合成基因簇，从而发现新的活性化合物。通过全基因组精细测序，PCR补洞和端粒的克隆测序，我们获得了全基因组精细图，并完成了基因组注释；基因组信息学分析预测了33个次级代谢产物生物合成基因簇，通过实时定量RT-PCR方法考察了其中关键酶基因的表达情况；通过调控球孢链霉菌多效性因子AtrA-gl，提高了铁载体生物合成基因簇的表达，分离到3个铁载体，其一是Desferrioxamine E；通过对8个隐形基因簇中途径特异性调控因子或转运蛋白的遗传操作，成功激活了4个基因簇的表达，分离到4个可能的新结构的化合物，具体化合物结构及生物学功能正在解析中。以基因组发掘策略应用于寻找球孢链霉菌新型天然产物，将揭示更多新型活性产物生物合成元件以及合成途径，为利用合成生物学技术进行创新微生物药物的研发奠定基础。