BRANCHED CHAIN AMINO ACID BIOSYNTHESIS IN E COLI

描述：(改编自调查人员摘要)：我们目前 对大肠杆菌中基因调控的理解提出了三个观点 控制等级：1)基础水平基因的全局控制 染色体结构表达；2)全球调控蛋白介导 刺激子和调节子的控制；以及，3)操纵子特定的控制。第一 控制水平的例证是依赖于DNA超螺旋的机制 描述了ILV操纵子的基础水平表达的协调 正规药。已经表明，这些控件可能会受到 染色体的拓扑结构，以及DNA结构蛋白 例如IHF能够调节这些分子的形成和位置 结构。本提案中描述的实验旨在进一步 描述这一全球基因调控的第一个层面。现建议： 染色体结构对基因表达的调节受 细胞的能量电荷，而这反过来又受到营养和 需要从一种增长状态转换到 又一个。为了验证这一想法，将使用计算和基因组方法。 DNA阵列将用于确定差异基因表达谱，以及 细胞能量电荷和DNA超螺旋水平将在 在存在和不存在IHF的情况下，好氧到厌氧生长的转变。 IHF结合位点的计算预测和IHF结合位点的预测 我们将利用大肠杆菌染色体的拓扑状态来分析这些数据。 预计这些实验将发现更多的操纵子， 对能量电荷和DNA超螺旋介导的信号做出响应，以进一步 人物刻画。这些实验将进一步提供丰富的 关于特定操纵子和全球操纵子的未来研究信息 有氧-厌氧过程中碳和能量代谢基因的调控 增长转型。

DESCRIPTION: (Adapted from the Investigator's abstract): Our current understanding of gene regulation in Escherichia coli suggests three hierarchical levels of control: 1) global control of basal level gene expression by chromosome structure; 2) global regulatory proteinmediated control of stimulons and regulons; and, 3) operon specific controls. The first level of control is exemplified by the DNA-supercoiling-dependent mechanisms described for the coordination of basal level expression of operons of the ilv regulon. It has been shown that these controls can be influenced by the topological structure of the chromosome, and that DNA architectural proteins such as IHF are able to modulate the formation and location of these structures. The experiments described in this proposal are designed to further characterize this first level of global gene regulation. It is proposed that regulation of gene expression by chromosome structure is influenced by the energy charge of the cell, which in turn is influenced by nutritional and environmental conditions that require transitions from one growth state to another. To test this idea, computational and genomic methods will be employed. DNA arrays will be used to determine differential gene expression profiles, and cellular energy charge and DNA supercoiling levels will be monitored during aerobic to anaerobic growth transitions in the presence and absence of IHF. Computational predictions of IHF binding sites and predictions of the topological state of the E. coli chromosome will be used to analyze these data. It is expected that these experiments will identify additional operons that respond to energy charge and DNA supercoiling-mediated signals for further characterization. These experiments will further provide a wealth of information for future studies concerning the operon specific and global regulation of carbon and energy metabolism genes during aerobic to anaerobic growth transitions.