Small RNAs Regulate Primary and Secondary Metabolism in Gram-negative Bacteria
- Authors: Maksym Bobrovskyy1, Carin K. Vanderpool2, Gregory R. Richards3
- Editors: Tyrrell Conway4, Paul Cohen5
-
VIEW AFFILIATIONS HIDE AFFILIATIONSAffiliations: 1: Department of Microbiology, University of Illinois, Urbana, IL 61801; 2: Department of Microbiology, University of Illinois, Urbana, IL 61801; 3: Biological Sciences Department, University of Wisconsin-Parkside, Kenosha, WI 53141; 4: Oklahoma State University, Stillwater, OK; 5: University of Rhode Island, Kingston, RI
-
Received 26 September 2014 Accepted 09 October 2014 Published 18 June 2015
- Correspondence: Gregory Richards, [email protected]

-
Abstract:
Over the last decade, small (often noncoding) RNA molecules have been discovered as important regulators influencing myriad aspects of bacterial physiology and virulence. In particular, small RNAs (sRNAs) have been implicated in control of both primary and secondary metabolic pathways in many bacterial species. This chapter describes characteristics of the major classes of sRNA regulators, and highlights what is known regarding their mechanisms of action. Specific examples of sRNAs that regulate metabolism in gram-negative bacteria are discussed, with a focus on those that regulate gene expression by base pairing with mRNA targets to control their translation and stability.
-
Citation: Bobrovskyy M, Vanderpool C, Richards G. 2015. Small RNAs Regulate Primary and Secondary Metabolism in Gram-negative Bacteria. Microbiol Spectrum 3(3):MBP-0009-2014. doi:10.1128/microbiolspec.MBP-0009-2014.




Small RNAs Regulate Primary and Secondary Metabolism in Gram-negative Bacteria, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/microbiolspec/3/3/MBP-0009-2014-1.gif /docserver/preview/fulltext/microbiolspec/3/3/MBP-0009-2014-2.gif

References

Article metrics loading...
Abstract:
Over the last decade, small (often noncoding) RNA molecules have been discovered as important regulators influencing myriad aspects of bacterial physiology and virulence. In particular, small RNAs (sRNAs) have been implicated in control of both primary and secondary metabolic pathways in many bacterial species. This chapter describes characteristics of the major classes of sRNA regulators, and highlights what is known regarding their mechanisms of action. Specific examples of sRNAs that regulate metabolism in gram-negative bacteria are discussed, with a focus on those that regulate gene expression by base pairing with mRNA targets to control their translation and stability.

Full text loading...
Figures

Click to view
FIGURE 1
Simplified network of sRNAs regulating biofilm formation and motility in Escherichia coli. The regulatory network shows a set of sRNAs (in bold) and relevant protein factors (grey boxes) controlling csgD (blue circle), flhDC (red circle) and pgaA (violet circle) at the transcriptional (dashed lines), translational (solid lines) and protein (dotted lines) levels. Other factors known to regulate csgD, flhDC, and pgaA were omitted for clarity. Arrows indicate activating interactions, and lines with blunt ends indicate inhibitory interactions.

Click to view
FIGURE 2
Quorum sensing systems of Vibrio cholerae. V. cholerae uses histidine kinases CqsS and LuxPQ to sense autoinducers (AIs) CAI-1 (violet triangle) and AI-2 (orange triangle) respectively. Receptors function as kinases at low cell density (LCD), when concentrations of CAI-1 and AI-2, which are produced by CqsA and LuxS, respectively, are low. This stimulates σ54-dependent activation of qrr gene expression through LuxU and LuxO phosphorylation cascade. The Qrr 1-4 sRNAs (red square), facilitated by Hfq, activate aphA, which stimulates expression of toxT, a known activator of the major virulence factors. Additionally Qrr 1-4 repress hapR, which leads to polysaccharide production and biofilm formation. Qrr 1-4 also negatively regulate genes for biogenesis of type VI secretion system (T6SS). In contrast, at high cell density (HCD) receptors sense the presence of AIs and function as phosphatases that stimulate dephosphorylation of LuxU, resulting in cessation of qrr expression. In the absence of Qrr sRNAs, hapR expression increases, which leads to the inhibition of biofilm formation and shut down of virulence factor production, while stimulating T6SS biosynthesis. Lines with arrowheads indicate activating interactions, and lines with blunt ends indicate inhibitory interactions.
Supplemental Material
No supplementary material available for this content.