The small RNA SgrS controls sugar-phosphate accumulation by regulating multiple PTS genes
Jennifer B Rice1, Carin K Vanderpool
1Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Nucleic Acids Research
|January 20, 2011
Summary
The small RNA SgrS regulates bacterial stress responses by controlling glucose and mannose transporters. This regulation, primarily translational, prevents sugar-phosphate stress by limiting substrate uptake.
Area of Science:
- Microbiology
- Molecular Biology
- Gene Regulation
Background:
- Bacterial small RNAs (sRNAs) are key regulators of stress responses.
- SgrS is an sRNA induced by glucose-phosphate stress.
- SgrS previously shown to target ptsG mRNA, encoding the major glucose transporter.
Purpose of the Study:
- To investigate the role of SgrS in regulating the manXYZ operon, encoding mannose and secondary glucose transporters.
- To elucidate the mechanism of SgrS-mediated regulation of manXYZ.
- To determine the contribution of PTS transporters to glucose-analogue-induced stress.
Main Methods:
- Analysis of manXYZ mRNA stability and translation in the presence and absence of SgrS.
- In vitro footprinting and in vivo mutational analyses to determine SgrS binding site.
- Construction and phenotypic analysis of Escherichia coli ptsG and ptsG manXYZ mutant strains.
Main Results:
- SgrS regulates manXYZ expression under stress conditions and upon ectopic expression.
- SgrS base pairs with manXYZ mRNA within the manX coding sequence, inhibiting translation.
- Regulation of manX by SgrS does not require the RNase E degradosome complex.
- A ptsG manXYZ double mutant is resistant to stress induced by glucose analogs, unlike a ptsG single mutant.
Conclusions:
- SgrS directly regulates manXYZ at the translational level.
- SgrS-mediated translational repression of manXYZ contributes to managing glucose-phosphate stress.
- Both PtsG and ManXYZ transporters play roles in the uptake of stress-inducing sugar analogs.
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