DNA segregation during Bacillus growth and development

这个建议的目的是确定质粒DNA partitioningsystems是积极的，在这两个。 营养生长和孢子形成的两种不同的芽孢杆菌。用于阐明 将使用模式生物B开发质粒分离的潜在机制。枯草芽抱杆菌w及 然后应用于B。巨大的利用两种不同的芽孢杆菌菌株来研究这个问题将使我们能够 利用每种生物及其固有质粒提供的独特优势， 保持一个集中的目标，了解如何保存微生物DNA分离的元素， 在孢子形成过程中，这种机制发挥作用，以确保每个孢子继承至少一个质粒拷贝。 孢子形成过程中的质粒分离为研究DNA分离提供了一个有吸引力的系统 因为：1）质粒和孢子形成过程都不是不必要的; 2）近10倍的 与母细胞相比，前孢子体积较小，需要有效的质粒分配 系统; 3）细胞特异性转录因子在孢子形成过程中变得活跃，从而允许孢子的发育。 强大的遗传和细胞生物学分析在孢子形成过程中的DNA分离;和4）许多芽孢杆菌 质粒不编码与质粒分离蛋白的帕拉或ParM家族相关的蛋白， 这表明新的分配机制正在起作用。由于各种各样的毒力因子 编码的质粒在致病菌株的芽孢杆菌，了解质粒是如何从一个 从下一代到下一代对于理解进化和传播这些关键毒力是重要的 决定因素这些研究将有助于开发更好的遗传工具和质粒载体， 操纵许多芽孢杆菌物种。

The goal of this proposal is to identify plasmid DNA partitioning systemsthat are active during both . vegetative growth and sporulation in two different species of Bacillus. New tools for elucidating the mechanisms underlying plasmid segregation will be developed using the model organism B. subtilis, and then applied to B. megaterium. Utilizing two different Bacillus strains to study this problem will allow us to take advantage of the unique strengths that each organism and its indigenous plasmids offer, while maintaining a focused goal of understanding how conservedelements of the microbial DNA segregation machinery functions during sporulation to ensure that every spore inherits at least one copy of the plasmid. Plasmid segregation during sporulation provides an attractive system for studying DNA segregation because: 1) both the plasmids and the sporulation process are not nonessential; 2) the nearly 10 fold smaller volume of the forespore comparedto the mothercell demands an efficient plasmid partitioning system; 3) cell-specifictranscription factorsbecome active during sporulation, allowing the development of . powerful genetic and cell biology assaysfor DNA segregation during sporulation; and 4) many Bacillus plasmids do not encode proteins related to either the ParA or ParM families of plasmid segregation proteins, suggesting that novel partitioning mechanisms are at work. Since a wide variety of virulence factors are encoded on plasmids in pathogenic strains of Bacillus, understanding how plasmids are transmitted from one generation to the next is important for understanding the evolution and spread these key virulence determinants. These studies will allow the development of better genetic tools and plasmid vectors useful for manipulating many Bacillus species.