ACTIVITY OF A PLASMID-BORNE LEU-500 PROMOTER DEPENDS ON THE TRANSCRIPTION AND TRANSLATION OF AN ADJACENT GENE
ACTIVITY OF A PLASMID-BORNE LEU-500 PROMOTER DEPENDS ON THE TRANSCRIPTION AND TRANSLATION OF AN ADJACENT GENE
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DOI：
10.1073/pnas.89.18.8784
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发表时间：
1992-09-15
影响因子：
11.1
通讯作者：
LILLEY, DMJ
中科院分区：
文献类型：
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作者：
CHEN, DR;BOWATER, R;LILLEY, DMJ
leu-500 是鼠伤寒沙门氏菌中的一种染色体启动子突变，通常会导致启动子在 RNA 合成起始阶段失活。但在编码 DNA 拓扑异构酶 I 的基因 topA 发生突变的菌株中，突变启动子变得活跃。我们证明，当 leu-500 启动子与四环素抗性基因 tetA 相邻时，它可以在质粒上发挥作用。 leu-500启动子的激活需要tetA基因的转录和翻译并且宿主细胞是topA。我们建议 leu-500 启动子 -10 区域中的 A --> G 突变通过 tetA 基因转录产生的局部负超螺旋来补偿，如果由于 TetA 肽锚定在膜中而减少扩散耗散，则在 topA 背景中可能会达到升高的水平。这是一个启动子活性通过另一个顺式启动子的活性调节的明显例子，当它们可以通过模板的拓扑结构耦合时。
leu-500 is a chromosomal promoter mutation in Salmonella typhimurium that normally causes the promoter to be inactive in the initiation of RNA synthesis. But in a strain that has mutations in topA, the gene encoding DNA topoisomerase I, the mutant promoter becomes active. We show that the leu-500 promoter can function on a plasmid when it is adjacent to the tetracycline-resistance gene tetA. Activation of the leu-500 promoter requires that the tetA gene is transcribed and translated and that the host cell is topA. We propose that the A --> G mutation in the -10 region of the leu-500 promoter is compensated by local negative supercoiling arising from transcription of the tetA gene, which may reach elevated levels in a topA background, provided that diffusional dissipation is reduced due to anchoring of the TetA peptide in the membrane. This is a clear example of the modulation of the activity of a promoter by the activity of another promoter in cis, when they can be coupled through the topology of the template.