MOLECULAR MECHANISMS OF STRESS-INDUCED MUTATION

应激诱发突变的分子机制

• 批准号: 9277153
• 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/9277153
• 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; 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.

基因组不稳定性推动癌症、病原体对宿主的适应以及对抗药性的进化 病原体和抗癌药物。与突变纯粹发生的经典假设不同 随机地以恒定和渐进的速度，微生物、植物、苍蝇和人类癌细胞 应激反应上调突变的机制。在细菌和类似的细菌中发现 生命之树，这些机制产生短暂的遗传多样性爆发，可以推动进化 尤其是当细胞不能很好地适应环境时--当受到压力时。应激诱导突变 机制可能为驱动病原体-宿主适应的基因变化提供更好的模型，抗生素 耐药、衰老、癌症进展和治疗耐药机制，以及可能的大部分进化 一般说来。这项建议解决了压力反应如何上调突变，以及如何阻止它们： 根本性的和医学上的紧迫问题。我们建议研究两个应激诱导的突变 大肠杆菌中的机制：突变DNA断裂修复(MBR)和抗生素诱导的突变：模型 用于在许多医学关键环境中进行突变。两者都需要一般的、严格的和DNA损伤 应激反应，这使得容易出错的DNA聚合酶促进突变。我们的方法将整合 使用捕获DNA的工程蛋白的实验基因组、遗传学、合成和单细胞策略 反应中间体，都在活细胞中。我们将从四个方面解决受监管的突变问题： ·发现细胞如何及时调节MBR。哪个基因(S)被一般上调或下调 应激反应引发突变断裂修复？通过什么机制？严苛的 应激反应独立促进饥饿和抗生素诱导的MBR？ ·在单细胞中发现MBR调节。四种应激反应促进MBR，其中一些被激活 细胞亚群。我们将确定哪些亚群经历了突变并阐明了 分化为一种可变状态--一种可能的进化性“押注对冲”策略。 ·发现细胞如何限制基因组空间的突变。我们将绘制自发的DNA断裂图谱 基因组，并解开它们的原因。我们将发现是更多的中断，更多的中断修复，还是其他 导致针对多个突变热点的特定大基因组区域。 ·抗生素诱发的突变。我们将剖析抗生素诱导的分子机制 诱变作用类似于膜生物反应器。我们将开发以突变为靶点的新药作为可能的抗生素 辅助药物，以减缓病原体的进化，并作为抗癌战略的典范。 该项目包括与开拓性的化学家、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重要的模型来理解和 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。