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Updated: May 19, 2026
06:30
A Non-Coding Small RNA MicC Contributes to Virulence in Outer Membrane Proteins in Salmonella Enteritidis
Published on: January 27, 2021
A complex network of small non-coding RNAs regulate motility in Escherichia coli
Nicholas De Lay1, Susan Gottesman
1Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892-4264, USA.
Molecular Microbiology
|August 29, 2012
Summary
Small regulatory RNAs (sRNAs) control bacterial behavior by interacting with messenger RNAs. In E. coli, multiple sRNAs fine-tune flagellar synthesis (flhDC) expression, integrating environmental signals through the flhDC mRNA's 5' untranslated region.
Area of Science:
- Microbiology
- Bacterial genetics
- RNA biology
Background:
- Small non-coding regulatory RNAs (sRNAs) are crucial regulators of bacterial gene expression.
- In Escherichia coli, flagellar synthesis is controlled by the master regulators FlhD and FlhC, encoded by the co-transcribed flhDC genes.
- The flhDC promoter is regulated by transcription factors responding to environmental cues.
Purpose of the Study:
- To investigate the role of sRNAs in regulating flhDC expression and bacterial motility.
- To identify specific sRNAs that interact with the flhDC mRNA.
- To elucidate the mechanisms by which sRNAs integrate environmental signals to control flagellar synthesis.
Main Methods:
- Analysis of sRNA-mRNA interactions using base-pairing with the 5' UTR of flhDC mRNA.
- Assessing the impact of sRNAs on motility and flhDC expression.
- Investigating the role of the ArcB/A two-component system in regulating sRNA expression.
Main Results:
- Four sRNAs (ArcZ, OmrA, OmrB, OxyS) negatively regulated flhDC expression and motility.
- One sRNA (McaS) positively regulated flhDC expression and motility.
- MicA positively regulated motility independently of flhDC regulation.
- ArcB/A system regulates motility partly through ArcZ.
- flhDC mRNA is the first shown to be both positively and negatively regulated by sRNAs.
- McaS and ArcZ share a common binding site on flhDC mRNA.
Conclusions:
- The 5' UTR of flhDC mRNA acts as a regulatory hub for integrating environmental signals via sRNAs.
- Bacterial motility is finely tuned by a complex network of sRNAs, including both positive and negative regulators.
- The interplay between sRNAs and the flhDC mRNA provides a sophisticated mechanism for bacterial adaptation to environmental changes.
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