Regulation of the Genes for E. Coli DNA Gyrase: Homeostatic Control of DNA Supercoiling

Cell. 1983 Aug;34(1):105-13. doi: 10.1016/0092-8674(83)90140-x.


DNA gyrase is the bacterial enzyme responsible for converting circular DNA to a negatively supercoiled form. We show that the synthesis of DNA gyrase is itself controlled by DNA supercoiling; synthesis is highest when the DNA template is relaxed. The rates of synthesis in vivo of both the A and B subunits of DNA gyrase are increased up to 10-fold by treatments that block DNA gyrase activity and decrease the supercoiling of intracellular DNA. Similarly, efficient synthesis of both gyrase subunits in a cell-free S-30 extract depends on keeping the closed circular DNA template in a relaxed conformation. The results suggest that DNA supercoiling in E. coli is controlled by a homeostatic mechanism. Synthesis of the RecA protein and several other proteins is also increased by treatments that relax intracellular DNA.

MeSH terms

  • Bacterial Proteins / biosynthesis
  • DNA Topoisomerases, Type II / biosynthesis*
  • DNA Topoisomerases, Type II / genetics
  • DNA, Bacterial / metabolism*
  • DNA, Superhelical / metabolism*
  • Escherichia coli / enzymology
  • Escherichia coli / genetics*
  • Gene Expression Regulation*
  • Genes, Bacterial
  • Homeostasis
  • Rec A Recombinases


  • Bacterial Proteins
  • DNA, Bacterial
  • DNA, Superhelical
  • Rec A Recombinases
  • DNA Topoisomerases, Type II