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Excellence in Research: Coupling of DNA Replication and Cell Division at Low Temperature in E. coli

卓越研究：大肠杆菌低温 DNA 复制与细胞分裂的耦合

基本信息

批准号：
2101124
负责人：
Pamela Jones
金额：
$ 49.03万
依托单位：
Winston-Salem State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-01 至 2024-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2101124&HistoricalAwards=false
关键词：
Excellence Research Coupling DNA Replication

项目摘要

Adverse environmental conditions such as extreme temperatures can have deleterious effects on cellular structures, processes and growth. Bacteria often encounter temperatures that are at or near their minimum temperature of growth. At temperatures just above the minimum temperature of growth, bacteria adapt and grow by inducing physiological changes that counteract the damaging effects of the cold stress. The long term goal of this project is to characterize the adaptive response to cold stress and identify factors that determine the minimum temperature of growth. In the bacterium Escherichia coli, an adaptive physiological change in response to low temperature is a decrease in cell size. Several proteins that function in DNA replication and cell division are specifically required for this adaptation. This research project aims to determine the connection between replication and cell division that facilitates growth and small cell size at cold temperatures. Broader impacts include the importance of understanding bacterial survival at cold temperatures because of our use of refrigeration in preserving and selling food. Additionally, the project will broaden participation by providing closely-mentored, hands-on research experience to train undergraduate students from groups that are underrepresented in STEM fields.The E. coli minimum temperature of growth is just above 8oC. The cells adapt to low temperature by increasing cell division and thereby reducing cell size. Compared to the large rods formed at 37oC, wild type E. coli are smaller rods at temperatures just above 8oC and filamentous rods at temperatures below the minimum temperature of growth. Late cell division proteins FtsN and DedD, which stimulate septal peptidoglycan synthesis and septation, are specifically required for growth and the formation of small rods at low temperature. A nucleoid-associated protein that enhances DNA replication is also required for growth and the production of the small rods. This project aims to test the hypothesis that replication and cell division are intricately linked, facilitating the small cell size and enabling growth at low temperatures. This hypothesis will be tested using two approaches. Flow cytometric and nucleoid staining analyses of the various cold-sensitive mutants will be performed to investigate the requirement for specific cell division and nucleoid-associated proteins for DNA replication at low temperature. Genetic screens will be done to identify suppressors of the cold-sensitive mutations, thereby elucidating the proteins required to couple DNA replication and cell division at low temperature. This research project should give novel insights into the differential requirements for the progression of the cell cycle as a function of temperature.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

恶劣的环境条件，如极端温度，会对细胞结构、过程和生长产生有害影响。细菌经常遇到处于或接近其最低生长温度的温度。在刚刚高于生长最低温度的温度下，细菌通过诱导生理变化来适应和生长，这些生理变化抵消了冷应激的破坏性影响。该项目的长期目标是表征对冷胁迫的适应性反应，并确定决定生长最低温度的因素。在大肠杆菌中，对低温的适应性生理变化是细胞大小的减小。这种适应特别需要一些在DNA复制和细胞分裂中起作用的蛋白质。该研究项目旨在确定在低温下促进生长和小细胞大小的复制和细胞分裂之间的联系。更广泛的影响包括了解细菌在低温下存活的重要性，因为我们在保存和销售食物时使用了冷藏。此外，该项目将通过提供密切指导和实践研究经验来培养来自STEM领域代表性不足群体的本科生，从而扩大参与范围。大肠杆菌的最低生长温度刚刚超过8摄氏度。细胞通过增加细胞分裂从而减小细胞大小来适应低温。与37℃下形成的大棒状菌相比，野生型大肠杆菌在8℃以上的温度下形成较小的棒状菌，在低于最低生长温度的温度下形成丝状菌。细胞后期分裂蛋白FtsN和DedD刺激间隔肽聚糖的合成和分裂，是低温下小棒生长和形成所必需的。一种促进DNA复制的核相关蛋白也是小杆状体生长和产生所必需的。这个项目旨在测试复制和细胞分裂是复杂联系的假设，促进小细胞尺寸和在低温下生长。这一假设将通过两种方法进行检验。流式细胞术和类核染色分析将对各种冷敏感突变体进行分析，以研究低温下DNA复制对特定细胞分裂和核相关蛋白的需求。将进行遗传筛选以确定冷敏感突变的抑制因子，从而阐明低温下DNA复制和细胞分裂耦合所需的蛋白质。这一研究项目将对温度对细胞周期进程的不同要求提供新的见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。