SPECIFIC AND GLOBAL CONTROL OF THE E. COLI ILVB OPERON

了解基因表达是如何控制的，这是 阐明细胞正常和异常生长的机制 和差异化。最近的事态发展表明，一些 不同的调节电路用于控制个体 细菌操纵子以及将这些途径的产物整合到 细胞的一般新陈代谢。这些数据表明，这些 生物合成系统可能是发现基因如何 在复杂和简单的生物体中，表达都受到调控。有了这个 有鉴于此，我们希望继续研究涉及控制的机制 在大肠杆菌K-12中的ilvB操纵子。各种监管要素包括 在该系统中运行，包括通过以下方式的多价最终产物衰减 多种tRNA、3‘，5’-二焦磷酸鸟苷、环状AMP和 集成主机因素。关于个体机制的研究 将对控制系统以及这些系统如何相互作用进行研究 无论是在体内还是体外。启动子调控区的序列 已经确定，克隆的片段将用于转录 确认启动子和调控基因的位置和性质的研究 区域。体内研究人员将专注于与 放射性标记的RNA和ilvB DNA片段探针已经确定 调控启动子区域的区域。此外，该机制和 各种监管要素之间的相互作用将在 体外转录-翻译耦合系统。

The understanding of how gene expression is controlled is fundamental in elucidating the mechanisms involved in normal and abnormal cellular growth and differentiation. Recent developments indicate that a number of different regulatory circuits are operative in controlling individual bacterial operons and in integrating the products of these pathways into the general metabolism of the cell. These data suggest that these biosynthetic systems may be valuable models for discovering how gene expression is regulated in complex as well as simple organisms. With this in mind we wish to continue out study of the mechanisms involved in control of the ilvB operon in E. coli K-12. A variety of regulatory elements are operative in this system including multi- valent endproduct attenuation by multiple species of tRNA, guanosine 3', 5'-bispyrophosphate, cyclic AMP and integration host factor. Studies on the mechanism of the individual control systems as well as how these systems interact will be investigated both in vivo and in vitro. The sequence of the promoter-regulatory region has been determined, and cloned fragments will be used in transcription studies to confirm the sites and nature of the promoter and regulatory region. In vivo investigators will focus on hybridization experiments with radioactively labelled RNA and ilvB DNA fragment probes which have defined regions of the regulatory-promoter region. In addition, the mechanism and interactions of the various regulatory elements will be investigated in a coupled in vitro transcription-translation system.