The Two-Component Response Regulator RcsB Regulates Type 1 Piliation in Escherichia coli

Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, Wisconsin 54601, USA.
Journal of Bacteriology (Impact Factor: 2.81). 11/2007; 189(19):7159-63. DOI: 10.1128/JB.00705-07
Source: PubMed


The ability of Escherichia coli cells to produce type 1 pili depends upon the orientation of the fimA promoter. The orientation depends upon the ratios of the FimB and FimE recombinases. Here, we report that the two-component
response regulator RcsB influences the piliation state by controlling fimB and fimE transcription.

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Available from: William R Schwan, Dec 30, 2013
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    • "According to this scenario, we supposed that both procaine and RfaH activate the pathway and that the cognate regulator of the system inhibits fimB transcription. It has been shown previously that fimB transcription is controlled by the response regulator RcsB that forms part of the Rcs phosphorelay system, a regulatory pathway that is also responsive to envelope stress (41). However, it was found that fimB transcription was unaffected by RcsB under the growth conditions used in this study and that the effect of procaine on the expression of the fimB-lacZ transcriptional fusion remained intact in this mutant background (data not shown). "
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    ABSTRACT: The phase variation (reversible on-off switching) of the type 1 fimbrial adhesin of Escherichia coli involves a DNA inversion catalyzed by FimB (switching in either direction) or FimE (on-to-off switching). Here, we demonstrate that RfaH activates expression of a FimB-LacZ protein fusion while having a modest inhibitory effect on a comparable fimB-lacZ operon construct and on a FimE-LacZ protein fusion, indicating that RfaH selectively controls fimB expression at the posttranscriptional level. Further work demonstrates that loss of RfaH enables small RNA (sRNA) MicA inhibition of fimB expression even in the absence of exogenous inducing stress. This effect is explained by induction of σE, and hence MicA, in the absence of RfaH. Additional work confirms that the procaine-dependent induction of micA requires OmpR, as reported previously (A. Coornaert et al., Mol. Microbiol. 76:467–479, 2010, doi:10.1111/j.1365-2958.2010.07115.x), but also demonstrates that RfaH inhibition of fimB transcription is enhanced by procaine independently of OmpR. While the effect of procaine on fimB transcription is shown to be independent of RcsB, it was found to require SlyA, another known regulator of fimB transcription. These results demonstrate a complex role for RfaH as a regulator of fimB expression.
    Full-text · Article · Oct 2013 · Journal of bacteriology
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    • "In particular, OmpR and RcsB in their phosphorylated form are inhibitors of flhD expression [24]. RcsB and OmpR are regulators of type I fimbriae [25,26], as well as expression of many other genes [27,28]. In planktonic E. coli, growth phase dependent expression of flhD required OmpR. "
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    ABSTRACT: Biofilms are communities of bacteria that are characterized by specific phenotypes, including an increased resistance towards anti-microbials and the host immune system. This calls for the development of novel biofilm prevention and treatment options to combat infectious disease. In Escherichia coli, numerous global regulators have been implicated in the control of biofilm associated cell surface organelles. These include the flagellar regulator FlhD/FlhC, the osmoregulator EnvZ/OmpR, and the colanic acid activator RcsCDB. Using flow cell technology and fluorescence microscopy, we determined the temporal expression from flhD::gfp, ompR::gfp, and rcsB::gfp in E. coli biofilm, as well as the impact of the negative regulation of flhD by OmpR and RcsB. Spatial gene expression was investigated from flhD::gfp. The temporal gene expression profile for flhD yielded an early peak at 12 h, a minimum of expression at 35 h, and a second increase in expression towards 51 h of biofilm development. In contrast, the ompR profile showed a peak at 35 h. A mutation in ompR abolished time dependence of flhD expression after the initial growth period of 12 h. Intriguingly, rcsB expression did not correlate inversely with flhD expression, yet a mutation in rcsB abolished time dependence of flhD expression as well. Spatially, expression of flhD was highest in the outermost layer of the biofilm in the parent strain. In ompR and rcsB mutants, flhD was expressed throughout the biofilm. Mutations in both, ompR and rcsB increased flhD expression throughout all temporal and spatial experiments. This increase was paralleled by reductions in biofilm amounts at four tested time points. Our data lead to the conclusion that FlhD/FlhC and its regulation by OmpR and RcsB may be our first target mechanism for the development of novel biofilm prevention and treatment techniques.
    Full-text · Article · Aug 2013 · BMC Microbiology
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    • "This means that mutants in ompR and rcsB exhibit increased flagellar synthesis relative to their wild-type parent (Fredericks et al. 2006; Oshima et al. 2002). For the rcsB mutant, this increase in the number of flagella appears to compensate for reduced levels of type I fimbriae (Schwan et al. 2007). "
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    ABSTRACT: The aim of this study was to develop an assay system that can quantify the amount of biomass in biofilms formed by different isogenic mutants of an Escherichia coli K-12 strain. The reported assay, which is based on the BacTiter-Glo assay from Promega, uses bioluminescence to detect the intracellular concentration of ATP, which correlates with viable bacterial cell numbers. The quantitative data obtained with this ATP assay were compared to those obtained with the conventional crystal violet assay. As a qualitative control, scanning electron microscopy was performed. The ATP assay, the crystal violet assay and scanning electron microscopy yielded similar results for six of the eight strains tested. For the remaining two strains, the images from the scanning electron microscopy confirmed the results from the ATP assay. The ATP assay, in combination with other quantitative and qualitative assays, will allow us to perform genetic studies on the regulatory network that underlies the early steps in E. coli biofilm formation.
    Full-text · Article · Jul 2009 · Letters in Applied Microbiology
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