Yanofsky C, Horn V
J Bacteriol. 1981 Mar;145(3):1334-41. doi: 10.1128/jb.145.3.1334-1341.1981.
Rifampin-resistant mutants of Escherichia coli were isolated which had altered patterns of resistance or sensitivity to the inhibitory compounds 5-methyltryptophan and 5-methylanthranilate. The levels of tryptophan (trp) operon polypeptides in different rifampin-resistant mutants were elevated or reduced, in a manner consistent with their sensitivity to the two analogs. Complementation tests established that the mutations were in rpoB, the structural gene for the beta subunit of ribonucleic acid polymerase. Introduction of these rpoB mutations into mutant strains which terminate transcription abnormally at the trp operon attenuator established that the rpoB mutations alter trp operon expression by increasing or decreasing transcription termination at the attenuator. The rpoB mutations affected transcription termination at the attenuator only in strains which were able to form what is thought to be a ribonucleic acid termination structure. These findings suggest that alteration of the beta subunit of ribonucleic acid polymerase directly or indirectly affects ribonucleic acid polymerase's recognition of the transcription termination signal at the trp operon attenuator.
分离出了对利福平耐药的大肠杆菌突变体，这些突变体对抑制性化合物5-甲基色氨酸和5-甲基邻氨基苯甲酸的耐药或敏感模式发生了改变。不同利福平耐药突变体中色氨酸（trp）操纵子多肽的水平升高或降低，这与它们对这两种类似物的敏感性一致。互补试验确定这些突变位于rpoB，即核糖核酸聚合酶β亚基的结构基因。将这些rpoB突变引入在trp操纵子衰减子处异常终止转录的突变菌株中，结果表明rpoB突变通过增加或减少衰减子处的转录终止来改变trp操纵子的表达。rpoB突变仅在能够形成被认为是核糖核酸终止结构的菌株中影响衰减子处的转录终止。这些发现表明，核糖核酸聚合酶β亚基的改变直接或间接影响核糖核酸聚合酶对trp操纵子衰减子处转录终止信号的识别。
