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.

基因组不稳定性导致癌症、病原体对宿主的适应以及抗药性的进化 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、苍蝇和人类癌细胞以恒定和渐进的速率随机地拥有 应激反应上调的突变机制。在细菌和类似的细菌中发现 在生命之树中，这些机制会产生短暂的遗传多样性爆发，从而推动进化 特别是当细胞无法适应环境时——即受到压力时。应激诱发突变 机制可能为驱动病原体-宿主适应、抗生素的遗传变化提供优越的模型 耐药性、衰老、癌症进展和治疗耐药机制，以及可能的大部分进化 一般来说。该提案讨论了应激反应如何上调诱变，以及如何阻止它们： 基本的和医学上紧迫的问题。我们建议研究两种应激诱导的突变 大肠杆菌的机制：诱变 DNA 断裂修复 (MBR) 和抗生素诱导的诱变：模型 用于许多医学关键环境中的诱变。两者都需要一般性、严格性和 DNA 损伤 应激反应，使容易出错的 DNA 聚合酶促进突变。我们的方法将整合 使用捕获 DNA 的工程蛋白进行实验基因组、遗传、合成和单细胞策略 反应中间体，全部在活细胞中。我们将从四个方向解决调控诱变问题： · 发现细胞如何及时调节MBR。哪些基因被一般上调或下调 应激反应是否会导致突变断裂修复的转变？通过什么机制？怎样严格 应激反应独立促进饥饿和抗生素诱导的 MBR？ · 发现单细胞中的 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经历诱变并阐明 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。我们将绘制自发 DNA 断裂图 基因组，并揭示其原因。我们将发现是否有更多的断裂、更多的断裂修复或其他 导致针对多个突变热点的特定大基因组区域。 · 抗生素诱导的突变。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来靶向诱变作为可能的抗生素 辅助剂，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、生物化学家和 分子生物学家。我们的共同目标是提供理解和理解的重要模型 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。