Sanzey B
J Bacteriol. 1979 Apr;138(1):40-7. doi: 10.1128/jb.138.1.40-47.1979.
Nalidixic acid (Nal), a drug which affects deoxyribonucleic acid gyrase activity, inhibits the expression of catabolite-sensitive genes: the three maltose operons, the lactose and galactose operons, and the tryptophanase gene. A correlation between the degree of sensitivity to Nal and that to catabolite repression has been observed. The expression of the threonine and tryptophan operons, insensitive to catabolite repression, is insensitive to Nal. The expression of the lacZ gene under the control of the IQ promoter is activated by Nal. Strains carrying a mutation in the nalA locus are resistant to these effects. Novobiocin, which inhibits the negative supercoiling activity of deoxyribonucleic acid gyrase, affects expression of the operons similarly to Nal. The involvement of promoters in Nal and novobiocin action, as well as a possible role of in vivo negative supercoiling in the selectivity of gene expression, are discussed.
萘啶酸（Nal）是一种影响脱氧核糖核酸回旋酶活性的药物，它会抑制分解代谢物敏感基因的表达：三个麦芽糖操纵子、乳糖和半乳糖操纵子以及色氨酸酶基因。已观察到对Nal的敏感程度与对分解代谢物阻遏的敏感程度之间存在相关性。对分解代谢物阻遏不敏感的苏氨酸和色氨酸操纵子的表达对Nal也不敏感。在IQ启动子控制下的lacZ基因的表达被Nal激活。nalA基因座发生突变的菌株对这些效应具有抗性。新霉素抑制脱氧核糖核酸回旋酶的负超螺旋活性，其对操纵子表达的影响与Nal类似。本文讨论了启动子在Nal和新霉素作用中的参与情况，以及体内负超螺旋在基因表达选择性中可能发挥的作用。
