SPECIFIC AND GLOBAL CONTROL OF THE E. COLI ILVB OPERON

了解基因表达是如何被控制的， 阐明正常和异常细胞生长的机制 和差异化。 最近的事态发展表明， 不同的调节电路可操作地控制个体 细菌操纵子，并将这些途径的产物整合到 细胞的一般代谢。 这些数据表明， 生物合成系统可能是发现基因 在复杂和简单的生物体中表达都受到调节。 与此 我们希望继续研究控制中涉及的机制， ilvB操纵子在E. coli K-12。 各种调控因素， 包括多价最终产物衰减， 多种tRNA、鸟苷3 '，5'-双焦磷酸、环AMP和 整合宿主因子 个体机制研究 控制系统以及这些系统如何相互作用将被调查 无论是在体内还是体外。 启动子调控区序列 已确定，克隆的片段将用于转录 研究以确认启动子和调节子的位点和性质， 地区 体内研究人员将专注于杂交实验， 放射性标记的RNA和ilvB DNA片段探针， 调节启动子区的区域。 此外，该机制和 各种调节元件的相互作用将在一个 体外转录-翻译系统。

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.