Roesser J R, Yanofsky C
Department of Biological Sciences, Stanford University, California 94305-5020.
J Biol Chem. 1988 Oct 5;263(28):14251-5.
The leader peptide stop codon (UGA) of the Escherichia coli trp operon was replaced by UAA and UAG. The transcriptional behavior of the mutated leader regions in vitro and the extent of transcription termination observed with each in vivo were virtually identical to that of the wild type leader region. Introduction of a release factor 1 (UAA- and UAG-specific) mutation into strains with the different stop codons caused increased termination in strains with UAA and UAG, but not with UGA (in cells grown in the presence of tryptophan). This finding provides evidence for the view that ribosome release from the leader peptide stop codon is an important event in setting the basal level of transcription readthrough at the trp attenuator.
将大肠杆菌色氨酸操纵子的前导肽终止密码子（UGA）替换为UAA和UAG。体外突变前导区的转录行为以及体内观察到的每种情况下的转录终止程度与野生型前导区几乎相同。在带有不同终止密码子的菌株中引入释放因子1（UAA和UAG特异性）突变，导致带有UAA和UAG的菌株中的终止增加，但带有UGA的菌株中没有增加（在色氨酸存在下生长的细胞中）。这一发现为以下观点提供了证据：核糖体从前导肽终止密码子处释放是设定色氨酸衰减子转录通读基础水平的一个重要事件。
