MOLECULAR MECHANISMS OF STRESS-INDUCED MUTATION

应激诱发突变的分子机制

• 批准号: 9751084
• 负责人: Susan M Rosenberg
• 金额: $ 50.78万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9751084
• 关键词: Address; Aging; Antibiotic Resistance; Antibiotics; Antineoplastic Agents; Bacteria; Cells; Chemotherapy-Oncologic Procedure; Collaborations; DNA; DNA Damage; DNA-Directed DNA Polymerase; Environment; Escherichia coli; Evolution; Genes; Genetic; Genetic Models; Genetic Variation; Genome; Genomic Instability; Genomic Segment; Genomics; Goals; Health; Human; Induced Mutation; Intervention; Life; Malignant Neoplasms; Maps; Medical; Microbe; Modeling; Molecular; Mutagenesis; Mutation; Pathogenesis; Plants; Protein Engineering; Reaction; Regulation; Resistance; Resistance development; Starvation; Stress; Time; Trees; anti-cancer; biological adaptation to stress; cancer cell; cancer therapy; combat; fly; microbial; novel therapeutics; pathogen; repaired; resistance mechanism; tool; tumor progression

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.

基因组不稳定性驱动器癌症，病原体对宿主的适应以及对抗抗性的抗性的演变 病原体和抗癌药。与纯粹发生突变发生的经典假设相反 随机地，恒定和等级速率，微生物，植物，苍蝇和人类癌细胞拥有 压力反应更新诱变的机制。在细菌中发现，在整个环境中相似 生命之树，这些机制产生了可以推动进化的遗传多样性的短暂爆发 压力诱导的妇女 机制可以为培养病原体宿主适应，抗生素的遗传变化提供卓越的模型 抗药性，衰老，癌症进展和耐药机制，可能是进化的大部分 一般来说。该提议解决了压力反应如何上调诱变，以及如何阻止它们： 基本和医学上的紧急问题。我们建议研究两个压力引起的妇女 大肠杆菌中的机制：诱变DNA断裂修复（MBR）和抗生素诱导的诱变：模型 在许多医学批判性环境中进行诱变。两者都需要一般，严格和DNA破坏 压力反应，允许容易出错的DNA聚合酶促进突变。我们的方法将整合 具有诱使DNA的工程蛋白质的实验基因组，遗传，合成和单细胞策略 反应中间，都在活细胞中。我们将从四个方向研究受管制的诱变： ·发现细胞如何调节MBR的时间。哪个基因被一般或下调 应力反应将转换转换为诱变断裂修复？通过什么机制？严格如何 压力反应独立促进饥饿和抗生素诱导的MBR？ 发现单细胞中MBR调节。四个压力反应促进MBR，其中一些被激活 细胞亚群。我们将确定哪些亚群经历诱变并照明 分化为可变状态，这是一种可能的进化“押注”策略。 发现细胞如何限制基因组空间中的突变。我们将绘制赞助的DNA断裂 基因组，并揭示其原因。我们将发现更多的断裂，更多的分手或其他 导致针对多个突变热点的特定特定大基因组区域。 抗生素诱导的诱变。我们将剖析抗生素诱导的分子机制 诱变类似于MBR。我们将开发新的药物以靶向诱变作为可能的抗生素 辅助，以减慢病原体的发展和作为模型抗癌策略。 该项目包括与开创性化学家，物理学家，生物信息学家，生物化学家和 分子生物学家。我们的共同目标是提供理解和了解的重要模型 干预上面列出的医疗问题以及打击抗生素耐药性的特定工具。