HISTIDINE OPERON: GENETIC CONTROL AND DNA SEQUENCE

本项目的主要目的是研究 鼠伤寒沙门氏菌组氨酸操纵子的遗传控制。 主要 对该操纵子表达的控制在转录水平， 利用衰减器机构。 我建议DNA测序 目标遗传控制信号中150个可用突变的数量， 随着M13克隆、经典重组和双脱氧 DNA测序方法。 我还将研究体外转录 突变的行为。 我会用足迹法来确定 在启动子处被RNA聚合酶识别的结合序列， 与衰减器的终止器动态地相互作用。 我建议确定整个组氨酸操纵子的DNA序列， 为此目的，制定一项改进的技术战略， 精确测序只需两到四个人工月 然后我将确定几个 操纵子基因中的突变碱基变化，从那些被 艾姆斯测试，它使用相同的DNA来测试可能的致癌物质， 环境化学品。

The chief objective of this project is to investigate the molecular mechanism of genetic control of the histidine operon of Salmonella typhimurium. The major control over expression of this operon is at the level of transcription, utilizing an attenuator mechanism. I propose to DNA sequence a substantial number of the 150 available mutations in the target genetic control signals, with the application of M13 cloning, classical recombination, and the dideoxy method of DNA sequencing. I will also investigate the in vitro transcription behavior of the mutations. I will apply the footprinting method to determine the binding sequences recognized by RNA polymerase at the promoter and while dynamically interacting with the terminator of the attenuator. I propose to determine the DNA sequence of the entire histidine operon, while developing an improved technical strategy for this purpose, so that 8 kb can be sequenced accurately in two to four man-months. I will then determine several mutational base changes in the genes of the operon, beginning with those used by the Ames test, which uses this same DNA to test for possible carcinogens among environmental chemicals.