The small RNA regulators of Escherichia coli: roles and mechanisms*

Annu Rev Microbiol. 2004;58:303-28. doi: 10.1146/annurev.micro.58.030603.123841.


Small noncoding RNAs have been found in all organisms, primarily as regulators of translation and message stability. The most exhaustive searches have taken place in E. coli, resulting in identification of more than 50 small RNAs, or 1%-2% of the number of protein-coding genes. One large class of these small RNAs uses the RNA chaperone Hfq; members of this class act by pairing to target messenger RNAs. Among the members of this class are DsrA and RprA, which positively regulate rpoS translation, OxyS, which negatively regulates rpoS translation and fhlA translation, RyhB, which reapportions iron use in the cell by downregulating translation of many genes that encode Fe-containing proteins, and Spot 42, which changes the polarity of translation in the gal operon. The promoters of these small RNAs are tightly regulated, frequently as part of well-understood regulons. Lessons learned from the study of small RNAs in E. coli can be applied to finding these important regulators in other organisms.

Publication types

  • Review

MeSH terms

  • Bacterial Outer Membrane Proteins / metabolism
  • Bacterial Proteins / metabolism
  • Base Pairing
  • Base Sequence
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Gene Expression Regulation, Bacterial / genetics
  • Host Factor 1 Protein / genetics
  • Host Factor 1 Protein / metabolism
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Protein Biosynthesis / physiology
  • RNA, Bacterial / genetics
  • RNA, Bacterial / metabolism
  • RNA, Bacterial / physiology*
  • RNA, Untranslated / genetics*
  • RNA, Untranslated / metabolism
  • Repressor Proteins / metabolism
  • Sigma Factor / metabolism
  • Transcription Factors / metabolism


  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • DrsA protein, E coli
  • Escherichia coli Proteins
  • Hfq protein, E coli
  • Host Factor 1 Protein
  • RNA, Bacterial
  • RNA, Untranslated
  • Repressor Proteins
  • Sigma Factor
  • Transcription Factors
  • oxyS protein, E coli
  • sigma factor KatF protein, Bacteria