RfaH Suppresses Small RNA MicA Inhibition of fimB Expression in Escherichia coli K-12

Moores, A., Chipper-Keating, S., Sun, L., McVicker, G. ORCID: 0000-0002-6967-5968, Wales, L., Gashi, K. and Blomfield, I.C., 2014. RfaH Suppresses Small RNA MicA Inhibition of fimB Expression in Escherichia coli K-12. Journal of Bacteriology, 196 (1), pp. 148-156. ISSN 0021-9193

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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 con- firms 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.

Item Type: Journal article
Publication Title: Journal of Bacteriology
Creators: Moores, A., Chipper-Keating, S., Sun, L., McVicker, G., Wales, L., Gashi, K. and Blomfield, I.C.
Publisher: American Society for Microbiology
Date: January 2014
Volume: 196
Number: 1
ISSN: 0021-9193
Identifiers:
NumberType
10.1128/JB.00912-13DOI
Divisions: Schools > School of Science and Technology
Depositing User: Jonathan Gallacher
Date Added: 12 Jan 2017 12:24
Last Modified: 09 Jun 2017 14:10
URI: http://irep.ntu.ac.uk/id/eprint/29657

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