Little R, Dennis P P
J Biol Chem. 1980 Apr 25;255(8):3536-41.
Amber mutations in the rpoB gene specifying the beta subunit of RNA polymerase coupled with conditional amber suppressors were used to restrict the synthesis of core RNA polymerase in strains of Escherichia coli. Such a restriction stimulated transcription of genetic units containing RNA polymerase subunit genes. Within the L10 transcription unit (genetic structure: promotor (PL10), rplJ (L10), rplL (L7/L12), attenuator, rpoB (beta), rpoC (beta'), terminator), the initiation of transcription at the promotor was enhanced and termination at the transcription attenuator was relaxed. Transcription of the genetic unit containing the rpoA gene (alpha) was also enhanced. In the strain containing a non-polar amber mutation, the synthesis rate of the beta' subunit protein during the restriction correlated with the level of transcription of the beta and beta' genes. In contrast, synthesis of L7/L12 ribosomal protein remained essentially unaltered in spite of the elevated levels of L10-L7/L12 mRNA.
在大肠杆菌菌株中，利用指定RNA聚合酶β亚基的rpoB基因中的琥珀突变与条件性琥珀抑制子相结合，来限制核心RNA聚合酶的合成。这种限制刺激了含有RNA聚合酶亚基基因的遗传单位的转录。在L10转录单位（遗传结构：启动子（PL10）、rplJ（L10）、rplL（L7/L12）、衰减子、rpoB（β）、rpoC（β'）、终止子）内，启动子处的转录起始增强，转录衰减子处的终止松弛。含有rpoA基因（α）的遗传单位的转录也增强。在含有非极性琥珀突变的菌株中，限制期间β'亚基蛋白的合成速率与β和β'基因的转录水平相关。相比之下，尽管L10 - L7/L12 mRNA水平升高，但L7/L12核糖体蛋白合成基本保持不变。
