Evolution of Function of Bacterial Nucleoid-associated Proteins

这个项目的重点是细菌类核的组织。细菌基因组与许多dna结合蛋白有关。一些蛋白，如HU蛋白，是普遍存在的，而另一些仅由真细菌的一个子集编码。Dps（饥饿期间DNA保护）蛋白属于后一类。主要目标是确定这些蛋白质家族中功能的分子决定因素。重点将是耐辐射真细菌耐辐射球菌，它编码一个HU和两个Dps同源物。对于D. radiodurans HU，其在首选底物（四向DNA连接）上的空间分布将通过位点定向诱变和光化学交联来确定。在类核组织中的作用将通过体内定位和分析正常指数生长期间的表达水平以及对DNA损伤的反应来评估。对于Dps-1，将在体外确定DNA相互作用的模式，并确定其作为生长条件或环境胁迫的函数的表达。由于预测Dps-2是非细胞质的，因此将确定其细胞定位，以及其DNA结合模式和对应激的调节。预计所提出的分析将不仅有助于我们对两个重要的核相关蛋白家族成员的DNA结合机制的理解，而且还有助于阐明有助于抗环境胁迫的细胞过程，这是耐辐射球菌的特征。这个项目的重点是通过为研究生和本科生提供获得研究经验的机会，将研究和教学结合起来。将强调少数民族学生的参与，并期望各级学生在国家会议上传播他们的研究。

The focus of this program is on the organization of the bacterial nucleoid. The bacterial genome is associated with a number of DNA-binding proteins. Some, such as HU proteins, are ubiquitous, while others are only encoded by a subset of eubacteria. Dps (DNA protection during starvation) proteins belong to the latter category. A main goal is to define molecular determinants of function within these protein families. The focus will be on the radiation-resistant eubacterium Deinococcus radiodurans which encodes one HU and two Dps homologs. For D. radiodurans HU, its spatial disposition on its preferred substrate, the four-way DNA junction, will be determined using site-directed mutagenesis and photochemical crosslinking. Roles in nucleoid organization will be assessed by in vivo localization and analysis of expression levels during normal exponential growth as well as in response to DNA damage. For Dps-1, the mode of DNA interaction will be determined in vitro and its expression as a function of growth condition or environmental stress will be determined. As Dps-2 is predicted to be non-cytoplasmic, its cellular localization will be determined, along with its mode of DNA binding and regulation in response to stress. It is anticipated that the proposed analyses will contribute not only to our mechanistic understanding of DNA binding by members of two important families of nucleoid-associated proteins, but also to elucidating cellular processes that contribute to the exceptional resistance to environmental stress that is characteristic of D. radiodurans. This program focuses on integrating research and teaching by offering the opportunity for both graduate and undergraduate students to acquire research experience. The involvement of minority students will be emphasized, and students at all levels will be expected to disseminate their research at national meetings.