Bacterial DNA topology and infectious disease

Nucleic Acids Res. 2009 Feb;37(3):672-8. doi: 10.1093/nar/gkn996. Epub 2008 Dec 10.


The gram-negative bacterium Escherichia coli and its close relative Salmonella enterica have made important contributions historically to our understanding of how bacteria control DNA supercoiling and of how supercoiling influences gene expression and vice versa. Now they are contributing again by providing examples where changes in DNA supercoiling affect the expression of virulence traits that are important for infectious disease. Available examples encompass both the earliest stages of pathogen-host interactions and the more intimate relationships in which the bacteria invade and proliferate within host cells. A key insight concerns the link between the physiological state of the bacterium and the activity of DNA gyrase, with downstream effects on the expression of genes with promoters that sense changes in DNA supercoiling. Thus the expression of virulence traits by a pathogen can be interpreted partly as a response to its own changing physiology. Knowledge of the molecular connections between physiology, DNA topology and gene expression offers new opportunities to fight infection.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Bacterial Infections / microbiology*
  • DNA, Bacterial / chemistry*
  • DNA, Superhelical / chemistry
  • Escherichia coli K12 / genetics*
  • Escherichia coli K12 / pathogenicity
  • Fimbriae, Bacterial / metabolism
  • Gene Expression Regulation, Bacterial
  • Promoter Regions, Genetic
  • Salmonella enterica / genetics*
  • Salmonella enterica / pathogenicity


  • DNA, Bacterial
  • DNA, Superhelical