Bacterial cell cycle control

描述(由申请人提供)：如何控制细胞周期事件与生长仍然是原核生物生物学中一个重要的、可能是最重要的、最突出的问题。一组与RAS相关的保守和必需的GTPase蛋白与细胞周期调控有关，但仍然缺乏特征。对Obg GTP酶的研究有可能阐明细菌中染色体分离的机制，目前尚不清楚。由于Obg是普遍保守和必不可少的，其功能对包括细菌病原体在内的所有细菌都有影响，并构成了抗生素治疗的潜在靶点。所有真核细胞也都具有Obg--其功能可能是线粒体所必需的--因此了解它在真核细胞生物学中的作用将是重要的，并将通过首先在原核生物中的研究来促进。一种结合了细胞可视化、遗传学、生物化学和生理学的综合方法，为理解这些重要而复杂的问题提供了机会。平移压力和细胞周期之间的联系将被研究。SEQA与染色体结合控制复制启动和染色体分离机制的假设将得到检验。在对细胞周期的严格反应控制中，将寻求其他因素。使用最先进的荧光显微镜，将检查大肠杆菌Obg蛋白的定位，以及它对细菌细胞骨架的影响，包括与肌动蛋白相关的MreB螺旋细丝，以及染色体和复制体的组织。将探索ObgE蛋白与几种蛋白质的相互作用，包括那些控制复制启动和染色体分离的蛋白质，即Obg可能发挥控制作用的过程。几个遗传筛选将探索ObgE和DNA结合蛋白SEQA在调节DNA复制和染色体分离中的作用。最后，将研究ObgE与核糖体的联系，以及严格反应和ObgE对核糖体功能和稳定性的影响。专业描述：我们将研究一种存在于所有细菌中的蛋白质，这种蛋白质似乎可以控制它们的生长。这将提供有关细菌如何分裂的重要缺失信息，并可能成为抗生素的靶标。

DESCRIPTION (provided by applicant): How cell cycle events are controlled with growth remains an important and perhaps the most important, outstanding question in prokaryotic biology. A group of conserved and essential GTPase proteins, related to Ras, have been implicated in cell cycle control but remain poorly characterized. The study of the Obg GTPase has the potential to elucidate aspects of the mechanism of chromosome segregation in bacteria, which is not, at present, understood. Because Obg is universally conserved and essential, its function has impacts on all bacteria, including bacterial pathogens, and constitutes a potential target for antibiotic therapy. All eukaryotic cells possess Obg, too-its function may be essential for mitochondria-and therefore its role in eukaryotic cell biology will be important to understand and will be facilitated by studies first in prokaryotes. An integrative approach, combining cell visualization, genetics, biochemistry and physiology, provides an opportunity to make headway into understanding these important and complex problems. The connection between translational stress and cell cycle will be investigated. The hypothesis that SeqA binding to the chromosome controls access to replication initiation and chromosome segregation machinery will be tested. Additional factors in the stringent response control of cell cycle will be sought. Using state-of- the-art fluorescence microscopy, the localization of the E. coli Obg protein will be examined, as well as its impact on bacterial cytoskeleton, including the actin-related MreB helical filament, and the organization of the chromosome and replisome. The interaction of the ObgE protein with several proteins, including those controlling replication initiation and chromosome segregation, processes on which Obg may exert control, will be probed. Several genetic screens will explore the role of ObgE and the DNA binding protein, SeqA in the regulation of DNA replication and chromosome segregation. Finally, the association of ObgE with the ribosome will be studied, as well as the impact of the stringent response and ObgE on ribosome function and stability. LAY DESCRIPTION: We will study a protein present in all bacteria that appears to control their growth. This will provide important missing information about how bacteria divide and may provide a target for antibiotics.