Bacterial cell cycle control

描述（由申请人提供）：细胞周期事件如何随生长而控制仍然是原核生物学中重要的，也许是最重要的，悬而未决的问题。与Ras相关的一组保守和必需的GTPase蛋白与细胞周期控制有关，但仍然缺乏特征。Obg GTPase的研究有可能阐明细菌染色体分离机制的各个方面，这是目前尚不清楚的。由于Obg是普遍保守和必需的，它的功能影响所有细菌，包括细菌病原体，并构成抗生素治疗的潜在靶点。所有真核细胞也都有Obg，它的功能可能对线粒体至关重要，因此它在真核细胞生物学中的作用将是重要的，并且将首先通过对原核生物的研究来促进。结合细胞可视化、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一个机会。我们将研究翻译应力与细胞周期的关系。SeqA与染色体结合控制复制起始和染色体分离机制的假设将被验证。在细胞周期的严格反应控制中的其他因素将被寻求。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螺旋丝，以及染色体和复制体的组织。ObgE蛋白与一些蛋白质的相互作用，包括那些控制复制起始和染色体分离的蛋白质，ObgE可能会发挥控制的过程，将被探索。几个基因筛选将探讨ObgE和DNA结合蛋白SeqA在DNA复制和染色体分离调控中的作用。最后，我们将研究ObgE与核糖体的关联，以及严格反应和ObgE对核糖体功能和稳定性的影响。LAY DESCRIPTION：我们将研究存在于所有细菌中的一种蛋白质，这种蛋白质似乎控制着细菌的生长。这将提供关于细菌如何分裂的重要信息，并可能提供抗生素的靶点。

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.