The stationary phase-specific sRNA FimR2 is a multifunctional regulator of bacterial motility, biofilm formation and virulence

Nucleic Acids Res. 2022 Nov 11;50(20):11858-11875. doi: 10.1093/nar/gkac1025.


Bacterial pathogens employ a plethora of virulence factors for host invasion, and their use is tightly regulated to maximize infection efficiency and manage resources in a nutrient-limited environment. Here we show that during Escherichia coli stationary phase the 3' UTR-derived small non-coding RNA FimR2 regulates fimbrial and flagellar biosynthesis at the post-transcriptional level, leading to biofilm formation as the dominant mode of survival under conditions of nutrient depletion. FimR2 interacts with the translational regulator CsrA, antagonizing its functions and firmly tightening control over motility and biofilm formation. Generated through RNase E cleavage, FimR2 regulates stationary phase biology by fine-tuning target mRNA levels independently of the chaperones Hfq and ProQ. The Salmonella enterica orthologue of FimR2 induces effector protein secretion by the type III secretion system and stimulates infection, thus linking the sRNA to virulence. This work reveals the importance of bacterial sRNAs in modulating various aspects of bacterial physiology including stationary phase and virulence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Biofilms
  • Escherichia coli Proteins* / genetics
  • Escherichia coli Proteins* / metabolism
  • Escherichia coli* / genetics
  • Escherichia coli* / metabolism
  • Escherichia coli* / pathogenicity
  • Gene Expression Regulation, Bacterial
  • RNA, Bacterial* / genetics
  • RNA, Bacterial* / metabolism
  • RNA, Small Untranslated / genetics
  • RNA, Small Untranslated / metabolism
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism
  • Virulence
  • Virulence Factors / genetics
  • Virulence Factors / metabolism


  • Bacterial Proteins
  • CsrA protein, E coli
  • Escherichia coli Proteins
  • ProQ protein, E coli
  • RNA, Bacterial
  • RNA, Small Untranslated
  • RNA-Binding Proteins
  • Virulence Factors