The DNA supercoiling‐sensitive expression of the Salmonella typhimurium his operon requires the his attenuator and is modulated by anaerobiosis and by osmolarity
- 1 September 1992
- journal article
- Published by Wiley in Molecular Microbiology
- Vol. 6 (17) , 2467-2476
- https://doi.org/10.1111/j.1365-2958.1992.tb01423.x
Abstract
Bacterial cells possess a subset of genes whose expression correlates with changes in DNA supercoiling brought about by anaerobic growth and by growth at high osmolarity. It has been shown previously that expression of the histidine biosynthetic operon of Salmonella typhimurium is derepressed by relaxation of supercoiled DNA. Here, we confirm that a his::MudJ operon fusion in S. typhimurium can be induced by treatment with the DNA gyrase inhibitor novobiocin in a dose-dependent manner, and show that the level of derepression is higher in stationary phase than in mid-exponential phase cultures. Furthermore, expression of his is repressed by anaerobiosis and by osmolarity, two environmental parameters which increase the negative supercoiling of bacterial DNA. Novobiocin induction of his is also repressed by growing the cells either at high osmolarity or anaerobically. Both environmental repression and novobiocin induction of his require the his attenuator. In addition, derepression of his expression by novobiocin and its repression by anaerobiosis or osmolarity are independent of the stringent response gene, relA.Keywords
This publication has 41 references indexed in Scilit:
- Control of bacterial DNA supercoilingMolecular Microbiology, 1992
- Bacterial DNA supercoiling andJournal of Molecular Biology, 1991
- GENETIC BASIS OF STARVATION SURVIVAL IN NONDIFFERENTIATING BACTERIAAnnual Review of Microbiology, 1989
- Osmotic regulation of porin expression: a role for DNA supercoilingMolecular Microbiology, 1989
- An overlap between osmotic and anaerobic stress responses: a potential role for DNA supercoiling in the coordinate regulation of gene expressionMolecular Microbiology, 1989
- A physiological role for DNA supercoiling in the osmotic regulation of gene expression in S. typhimurium and E. coliCell, 1988
- Escherichia coli DNA topoisomerase I mutants: Increased supercoiling is corrected by mutations near gyrase genesCell, 1982
- Role of a hisU gene in the control of stable RNA synthesis in Salmonella typhimuriumJournal of Molecular Biology, 1982
- DNA sequence changes of mutations altering attenuation control of the histidine operon of Salmonella typhimuriumJournal of Molecular Biology, 1981
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976