ppGpp: Magic Beyond RNA Polymerase

Nat Rev Microbiol. 2012 Feb 16;10(3):203-12. doi: 10.1038/nrmicro2720.


During stress, bacteria undergo extensive physiological transformations, many of which are coordinated by ppGpp. Although ppGpp is best known for enhancing cellular resilience by redirecting the RNA polymerase (RNAP) to certain genes, it also acts as a signal in many other cellular processes in bacteria. After a brief overview of ppGpp biosynthesis and its impact on promoter selection by RNAP, we discuss how bacteria exploit ppGpp to modulate the synthesis, stability or activity of proteins or regulatory RNAs that are crucial in challenging environments, using mechanisms beyond the direct regulation of RNAP activity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Bacterial Physiological Phenomena*
  • DNA-Directed RNA Polymerases / metabolism*
  • Environment
  • Gene Expression Regulation, Bacterial
  • Guanosine Tetraphosphate / metabolism*
  • Sigma Factor / metabolism


  • Sigma Factor
  • Guanosine Tetraphosphate
  • DNA-Directed RNA Polymerases