CAREER: Leveraging polycyclic tetramate macrolactam biosynthesis as a model for understanding actinobacterial metabolic silencing

放线菌产生了我们目前大多数的抗生素。它们的基因组可能含有更多的新型抗生素。然而，利用这些微生物的全部生物合成能力进行药物和农用化学品的发现是具有挑战性的。这是因为它们的大多数生物合成基因簇在实验室中缺乏可检测的产物。 这种现象，即预测的代谢途径不能产生预期的产物，被称为生物合成沉默。 作为生物活性分子发现的最大生物技术挑战之一，生物合成沉默有效地隐藏了产品开发中急需的新分子。这个NSF职业项目旨在揭示生物合成沉默的生物学基础。 这样做将揭示新的代谢调节模型，这将有助于激活沉默基因并分离其产物以供人类使用。重要的是，该项目需要多学科的方法，并在高中，本科和研究生院层面创造沉浸式的科学教育机会。 以多环四酸大环内酰胺（PTM）生物合成簇为模型，探讨丝状放线菌生物合成簇沉默的机制。PTM分子具有治疗上令人感兴趣的活性，并且它们的生物合成基因座在这些生物体中是很保守的。这种共性使得放线菌家族之间的比较代谢基因组学。系统评估PTM生产链霉菌灰色进化枝内的PI的小组表明沉默是由两个相互作用的机制：转录调控和代谢控制。 从表征这些机制中获得的经验教训将扩展到S. griseus小组对理解次级代谢调节的进化和诱导。总之，这项工作代表了比较代谢基因组学的首次系统应用，以揭示生物合成沉默的特定分子遗传和代谢原因。对机制的理解将可能揭示通过合成生物学进行治疗和农业化学发现的新策略，这是开发增强生产菌株和更强大的微生物功能基因组理解的基础。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

Actinomycete bacteria produce a majority of our current antibiotics. Their genomes may harbor many more novel antibiotics. However, harnessing the full biosynthetic capacity of these microorganisms for drug and agrichemical discovery is challenging. This is because the majority of their biosynthetic gene clusters lack detectable products in the laboratory. This phenomenon, where predicted metabolic pathways fail to yield expected products, is termed biosynthetic silence. Representing one of the greatest biotechnological challenges to bioactive molecule discovery, biosynthetic silencing effectively hides much-needed new molecules from product development. This NSF CAREER project is designed to reveal the biological underpinnings of biosynthetic silence. Doing this will reveal new models of metabolic regulation that will be useful for activating silent genes and isolating their products for human gain. Importantly, this project demands a multidisciplinary approach and creates immersive scientific education opportunities at the high school, undergraduate and graduate school levels. Using polycyclic tetramate macrolactam (PTM) biosynthetic clusters as a model, this proposal probes the mechanisms responsible for biosynthetic cluster silencing in filamentous actinobacteria. PTM molecules have therapeutically interesting activities and their biosynthetic loci are well- conserved among these organisms. This commonality enables comparative metabologenomics across actinomycete families. Systematic assessment of PTM production within the Streptomyces griseus clade by the PI's group suggests silencing is determined by two interacting mechanisms: transcriptional regulation and metabolic control. Lessons learned from characterizing these mechanisms will be extended to actinobacteria outside of the S. griseus group towards understanding the evolution and induction of secondary metabolic regulation. Together, this work represents the first systematic application of comparative metabologenomics to reveal specific molecular-genetic and metabolic causes of biosynthetic silencing. Mechanistic understanding will likely reveal new strategies for therapeutic and agrichemical discovery via synthetic biology, fundamental for development of enhanced producing strains and more robust microbial functional genomic understanding.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.