Growth Versus Maintenance: A Trade-Off Dictated by RNA Polymerase Availability and Sigma Factor Competition?

Mol Microbiol. 2004 Nov;54(4):855-62. doi: 10.1111/j.1365-2958.2004.04342.x.


The regulatory design of higher organisms is proposed to comprise a trade-off between activities devoted to reproduction and those devoted to cellular maintenance and repair. Excessive reproduction will inevitably limit the organism's ability to resist stress whereas excessively devoted stress defence systems may increase lifespan but reduce Darwinian fitness. The trade-off is arguably a consequence of limited resources in any one organism but the nature and identity of such limiting resources are ambiguous. Analysis of global control of gene expression in Escherichia coli suggests that reproduction and maintenance activities are also at odds in bacteria and that this antagonism may be a consequence of a battle between transcription factors for limiting RNA polymerase. The outcome of this battle is regulated and depends on the nutritional status of the environment, the levels of the alarmone ppGpp, and RNA polymerase availability. This paper reviews how the concentration of RNA polymerase available for transcription initiation may vary upon shifts between growth and growth-arrest conditions and how this adjustment may differentially affect genes whose functions relate to reproduction and maintenance.

Publication types

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

MeSH terms

  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • DNA-Directed RNA Polymerases / metabolism*
  • Diphosphates / metabolism
  • Escherichia coli / genetics
  • Escherichia coli / physiology*
  • Gene Expression Regulation, Bacterial*
  • Polymorphism, Genetic
  • Sigma Factor / genetics
  • Sigma Factor / metabolism*
  • Transcription, Genetic


  • Bacterial Proteins
  • Diphosphates
  • Sigma Factor
  • sigma factor KatF protein, Bacteria
  • DNA-Directed RNA Polymerases