DNA recombinational repair in Helicobacter pylori

幽门螺杆菌的 DNA 重组修复

• 批准号: 7847612
• 负责人: Ge Wang
• 金额: $ 22.28万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-22 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7847612
• 关键词: Bacteria; Bacterial DNA; Co-Immunoprecipitations; DNA; DNA Damage; DNA Repair; Environment; Exhibits; Frequencies; Gastric mucosa; Gene Proteins; Gene Targeting; Genes; Genetic Recombination; Genetic Variation; Goals; Helicobacter pylori; Human; Infection; Libraries; Light; Mitomycins; Mutagenesis; Peptic Ulcer; Proteins; Research Design; Role; Screening procedure; Series; Stomach; Stomach Diseases; System; Work; acid stress; crosslink; helicase; in vivo; insight; malignant stomach neoplasm; mouse model; mutant; novel; public health relevance; recombinational repair

DESCRIPTION (provided by applicant): Helicobacter pylori infects the stomachs of approximately 50% of humans and results in a series of human gastric diseases. It is highly adapted to maintain persistence in the human gastric mucosa, a niche full of oxidative and acid stress agents that cause bacterial DNA damage. H. pylori exhibits the highest level of genetic diversity known among bacteria, and a major contributor to this diversity is the high frequency of DNA recombination. We hypothesize that the repair of DNA damage by recombination both facilitates H. pylori's genetic diversity and contributes to its in vivo survival. H. pylori likely has a unique mechanism for DNA recombinational repair, particularly for the initial steps including the recognition of damaged DNA and subsequent recruitment of recombination repair proteins. The exploratory goals of this proposal are to define the roles of four putative proteins (RecN, RecJ, RecR, and HP1553) involved in DNA recombinational repair. Gene-targeted mutant strains in these 4 genes will be examined for their sensitivity to DNA damaging agents, for their survival under oxidative and acid stress conditions, and for their DNA recombination frequency. The roles of these genes/proteins in the in vivo survival of H. pylori will be studied using a mouse model of infection. A secondary exploratory goal is to identify additional components of the recombinational repair system in H. pylori by screening for mitomycin C-sensitive strains from a random transposon mutagenesis library. Alternatively, the proteins that interact with RecN, RecB, or RecR will be identified via cross-linking and coimmunoprecipitation approaches. Our studies are designed to shed light on H. pylori genes involved in the bacterium's unique ability to survive the gastric environment, and to provide novel insight into the unique mechanisms of DNA recombinational repair. PUBLIC HEALTH RELEVANCE: Helicobacter pylori persistently infects the human gastric mucosa and causes serious conditions such as peptic ulcer disease and gastric cancers. Studying the DNA recombinational repair system will help us understand how H. pylori can adapt to and persist in the human stomach.

描述（申请人提供）：幽门螺杆菌感染约50%人类的胃，导致一系列人类胃病。它高度适应于维持在人类胃粘膜中的持久性，胃粘膜是一个充满氧化和酸应激剂的生态位，可导致细菌 DNA 损伤。幽门螺杆菌表现出已知细菌中最高水平的遗传多样性，而这种多样性的一个主要贡献者是高频率的 DNA 重组。我们假设通过重组修复 DNA 损伤既促进幽门螺杆菌的遗传多样性，又有助于其在体内的存活。幽门螺杆菌可能具有独特的 DNA 重组修复机制，特别是对于包括识别受损 DNA 和随后招募重组修复蛋白在内的初始步骤。该提案的探索性目标是定义参与 DNA 重组修复的四种推定蛋白（RecN、RecJ、RecR 和 HP1553）的作用。将检查这 4 个基因中的基因靶向突变株对 DNA 损伤剂的敏感性、在氧化和酸应激条件下的存活情况以及 DNA 重组频率。将使用小鼠感染模型来研究这些基因/蛋白质在幽门螺杆菌体内存活中的作用。第二个探索性目标是通过从随机转座子诱变文库中筛选丝裂霉素 C 敏感菌株来鉴定幽门螺杆菌重组修复系统的其他成分。或者，与 RecN、RecB 或 RecR 相互作用的蛋白质将通过交联和免疫共沉淀方法进行鉴定。我们的研究旨在揭示幽门螺杆菌基因，该基因与细菌在胃环境中生存的独特能力有关，并为 DNA 重组修复的独特机制提供新的见解。公众健康相关性：幽门螺杆菌持续感染人类胃粘膜，导致消化性溃疡和胃癌等严重疾病。研究DNA重组修复系统将有助于我们了解幽门螺杆菌如何适应并在人类胃中持续存在。