MECHANISM AND REGULATION OF E COLI RNA POLYMERASE

这个项目的目的是调查关于 大肠杆菌转录启动的机制及其调控。 这些实验的目的是提供一个基本的生化 对认知过程中几个复杂现象的认识 大肠杆菌启动子的RNA聚合酶。一系列研究将 表征“闭合络合物”，一个重要的反应中间体 启动过程。在体外进行的实验也将 描述显示的突变西格玛亚基的特性 体内启动子识别的改变。DNA超螺旋效应对细胞生长的影响 将使用一种新开发的分析方法来探索启动子识别 拓扑异构体选择性。这一新方法将在一项研究中推广 由乳糖和半乳糖操纵子上的帽*cAMP正向调节 推动者。半乳糖对启动子选择性的调节 GAL启动子上的抑制子也将被描述。结构性的 RNA-RNA配对的决定因素也将在以下示例中确定 反义RNA基因调控。在这种情况下，规则发生 然而，主要是在翻译启动步骤中， 出现的RNA-RNA配对将适用于基因的许多其他步骤 表达及其调控。我们提出的问题的答案 将有助于对基因控制的生物化学描述 表情。

This project is designed to investigate important questions about the mechanism and regulation of transcription initiation in Escherichia coli. The experiments are designed to provide a fundamental biochemical understanding of several complex phenomena involved in the recognition of E. coli promoters by RNA polymerase. A series of studies will characterize the "closed complex", an important reaction intermediate in the initiation process. Experiments performed in vitro will also characterize the properties of a mutant sigma subunit that displays altered promoter recognition in vivo. The effects of DNA supercoiling on promoter recognition will be explored using a newly-developed assay for topoisomer selectivity. This novel approach will be extended in a study of positive regulation by cap*cAMP at the lactose and galactose operon promoters. The modulation of promoter selectivity by the galactose repressor at the gal promoters will also be characterized. The structural determinants of RNA-RNA pairing will also be determined in an example of antisense RNA gene regulation. In this case the regulation occurs primarily at the translation initiation steps, however, the principles for RNA-RNA pairing that emerge will be applicable to many other steps in gene expression and its regulation. The answers to the questions we have posed will contribute to the biochemical description of the control of gene expression.