Molecular mechanisms of stress-induced mutation

联系PD/PI：Rosenberg，Susan M. 基因组的不稳定性导致癌症，病原体对宿主的适应，以及对抗- 病原体和抗癌药物。与突变纯粹发生的经典假设相反， 微生物、植物、苍蝇和人类癌细胞具有恒定和渐进的速率， 应激反应上调的诱变机制。在细菌中发现， 作为生命之树的一部分，这些机制产生了可以推动进化的遗传多样性的短暂爆发 特别是当细胞对环境适应不良时-当受到压力时。胁迫诱发突变 这些机制可以为驱动病原体-宿主适应、抗生素和/或抗生素的遗传变化提供上级模型。 抵抗、衰老、癌症进展和治疗抵抗机制，以及可能的大部分进化 一般来说。该提案解决了应激反应如何上调诱变，以及如何阻止它们： 基本的和医学上紧急的问题。我们建议调查两个胁迫诱发的突变 E.大肠杆菌：致突变DNA断裂修复（MBR）和抗生素诱导的致突变：模型 在许多医学关键领域中的诱变。两者都需要一般的，严格的，和DNA损伤 应激反应，这允许易错DNA聚合酶促进突变。我们的方法将整合 实验基因组，遗传，合成和单细胞策略与工程蛋白质，陷阱DNA 反应中间体，都在活细胞中。我们将从四个方向解决调控诱变： ·发现细胞如何及时调节MBR。哪一个基因（S）上调或下调的一般 压力反应导致突变性断裂修复通过什么机制？严格的 应激反应独立促进饥饿和饥饿诱导MBR？ ·发现单个细胞中的MBR调节。四种应激反应促进MBR，其中一些在 细胞亚群我们将确定哪些亚群发生突变，并阐明 分化为可变状态-一种可能的进化“赌注对冲”策略。 ·发现细胞如何限制基因组空间中的突变。我们将绘制出 基因组，并解开其原因。我们将发现是否更多的断裂，更多的断裂修复，或其他 导致针对多个突变热点的靶向特定大基因组区域。 ·抗生素诱导的诱变。我们将剖析抗生素诱导的分子机制 类似于MBR的诱变。我们将开发新的药物靶向诱变作为可能的抗生素 它可以减缓病原体的进化，并作为抗癌策略的模型。 该项目包括与先驱化学家，物理学家，生物信息学家，生物化学家， 分子生物学家我们的共同目标是提供重要的模型， 对上述医疗问题的干预以及对抗抗生素耐药性的具体工具。 项目摘要/摘要第6页

Contact PD/PI: Rosenberg, Susan M. Genomic instability drives cancers, adaptation of pathogens to hosts, and evolution of resistance to anti- pathogen and anti-cancer drugs. In contrast with classical assumptions that mutations occur purely stochastically with constant and gradual rates, microbes, plants, flies and human cancer cells possess mechanisms of mutagenesis upregulated by stress responses. Discovered in bacteria and similar across the tree of life, these mechanisms generate transient bursts of genetic diversity that can propel evolution specifically when cells are poorly adapted to their environments—when stressed. Stress-induced-mutation mechanisms may provide superior models for genetic changes that drive pathogen-host adaptation, antibiotic resistance, aging, cancer progression and therapy-resistance mechanisms, and possibly much of evolution generally. This proposal addresses how stress responses upregulate mutagenesis, and how to stop them: fundamental and medically urgent problems. We propose to investigate two stress-induced-mutation mechanisms in E. coli: mutagenic DNA break repair (MBR), and mutagenesis induced by antibiotics: models for mutagenesis in many medically critical contexts. Both require the general, stringent, and DNA-damage stress responses, which allow error-prone DNA polymerases to promote mutations. Our approach will integrate experimental genomic, genetic, synthetic and single-cell strategies with engineered proteins that trap DNA reaction intermediates, all in living cells. We will address regulated mutagenesis from four directions: · Discovery of how cells regulate MBR in time. Which gene(s) up- or down-regulated by the general stress-response throw the switch to mutagenic break repair? By what mechanism? How does the stringent stress response independently promote starvation- and antibiotic-induced MBR? · Discovery of MBR regulation in single cells. Four stress responses promote MBR, some activated in cell subpopulations. We will determine which subpopulations undergo mutagenesis and illuminate differentiation into a mutable state—a possible evolutionary “bet hedging” strategy. · Discovery of how cells restrict mutations in genomic space. We will map spontaneous DNA breaks in genomes, and unravel their causes. We will discover whether more breaks, more break-repair, or other causes target specific large genomic regions for multiple mutation hotspots. · Antibiotic-induced mutagenesis. We will dissect a molecular mechanism of antibiotic-induced mutagenesis similar to MBR. We will develop novel drugs to target mutagenesis as possible antibiotic adjuncts, to slow evolution of pathogens, and as a model anti-cancer strategy. This project includes collaborations with pioneering chemists, physicists, bioinformaticians, biochemists, and molecular biologists. Our shared goal is to provide both important models for understanding of and intervention in the medical problems listed above and specific tools for combating antibiotic resistance. Project Summary/Abstract Page 6