Function of type1A topoisomerases in bacterial chromosome segregation

1A型拓扑异构酶在细菌染色体分离中的作用

• 批准号: 138803-2010
• 负责人: Drolet, Marc
• 金额: $ 2.91万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=545570
• 关键词: Function; type1A; topoisomerases; bacterial; chromosome

A key step in the life of a bacterial cell is its division to generate two identical daughter cells. This event allows its perpetuation from generation to generation. However, one key event that most be faithfully accomplish before cell division, is the segregation of the replicated genetic material (chromosomes) to each end of the cell, so that each daughter cell can receive one chromosome following division. With a full set of the genes from the mother cell, each daughter cell will be able to grow and divide. Because of the double-helical nature of the DNA, entanglement of the DNA strands inevitably occurs during replication. If not properly and rapidly removed, these intertwines will eventually block the progression of the replication complex and, as a consequence, chromosome segregation will not be possible. DNA topoisomerases, by cutting DNA and by allowing strand passage and religation solve the topological problem associated with the progression of replication complexes. Topoisomerases from the bacterium Escherichia coli have been well characterized in vitro in term of their catalytic properties and their ability to work during replication. However, little is known about their actual function in the cell and their regulation with the cell cycle. The main goal of our research project is to characterize the roles of the various DNA topoisomerases in chromosome replication and segregation in E. coli cells. Modern microscopic techniques allowing the visualization of chromosomes and proteins in living cells together with molecular biology, genetic and biochemical approaches will be used to characterize the roles of the various topoisomerases in the cell cycle. The ultimate goal of our research program is to understand how bacteria regulate the major events of their cell cycle to allow the faithful transmission of their genetic material to daughter cells.

细菌细胞生命中的关键一步是分裂，产生两个完全相同的子细胞。这一事件使其代代相传。然而，在细胞分裂前最忠实地完成的一个关键事件是将复制的遗传物质(染色体)分离到细胞的两端，这样每个子细胞在分裂后可以得到一条染色体。有了母细胞的全套基因，每个子细胞将能够生长和分裂。由于DNA的双螺旋性质，在复制过程中不可避免地会发生DNA链的纠缠。如果不能正确和迅速地去除，这些缠绕在一起的物质最终会阻碍复制复合体的发展，因此，染色体分离将是不可能的。DNA拓扑异构酶，通过切割DNA，允许链通过和宗教化，解决了与复制复合体进展相关的拓扑问题。大肠杆菌的拓扑异构酶在体外已经被很好地表征了它们的催化特性和在复制过程中工作的能力。然而，人们对它们在细胞中的实际功能以及它们对细胞周期的调节知之甚少。我们研究项目的主要目标是研究各种DNA拓扑异构酶在大肠杆菌细胞中染色体复制和分离中的作用。现代显微技术可以显示活细胞中的染色体和蛋白质，结合分子生物学、遗传学和生化方法，将被用来表征各种拓扑异构酶在细胞周期中的作用。我们研究计划的最终目标是了解细菌如何调节它们细胞周期的主要事件，以允许它们的遗传物质忠实地传递给子细胞。