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（由申请人提供）：幽门螺杆菌感染了大约50％的人类的胃，并导致一系列人类胃病。它高度适应于人类胃粘膜的持久性，人类胃粘膜是一种充满氧化和酸性胁迫剂的利基市场，引起细菌DNA损伤。幽门螺杆菌在细菌中表现出最高水平的遗传多样性，而导致这种多样性的主要因素是DNA重组的高频。我们假设通过重组修复DNA损伤都促进了幽门螺杆菌的遗传多样性，并有助于其体内生存。幽门螺杆菌可能具有DNA重组修复的独特机制，特别是对于初始步骤，包括识别受损的DNA和随后募集重组修复蛋白。该提案的探索性目标是定义与DNA重组维修有关的四种推定蛋白（RECN，RECJ，RERS和HP1553）的作用。这4个基因中的基因靶向突变菌株将检查其对DNA损伤剂的敏感性，在氧化和酸应激条件下的存活以及其DNA重组频率。这些基因/蛋白质在幽门螺杆菌的体内存活中的作用将使用小鼠感染模型进行研究。次要探索性目标是通过筛选从随机转座子诱变库中筛选丝裂霉素C敏感性菌株来鉴定幽门螺杆菌中重组修复系统的其他组成部分。或者，将通过交联和免疫沉淀方法来鉴定与RECN，RECB或RER相互作用的蛋白质。我们的研究旨在阐明该细菌在胃环境中生存独特的幽门螺杆菌基因，并提供对DNA重组修复独特机制的新颖洞察力。公共卫生相关性：幽门螺杆菌持续感染人类胃粘膜，并引起严重的疾病，例如消化性溃疡疾病和胃癌。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持续在人类胃中。