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

Moores, Alexandra, Chipper-Keating, Saranna, Sun, Lei, McVicker, Gareth, Wales, Lynn, Gashi, Krishna, Blomfield, Ian 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. E-ISSN 1098-5530. (doi:10.1128/JB.00912-13) (KAR id:81095)

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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 SigmaE, and hence MicA, in the absence of RfaH. Additional work confirms that the procaine-dependent induction of micA requires OmpR, as reported previously, 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: Article
DOI/Identification number: 10.1128/JB.00912-13
Uncontrolled keywords: Echerichia coli; FimB, FimE, RfaH
Subjects: Q Science > QR Microbiology
Divisions: Divisions > Division of Natural Sciences > Biosciences
Depositing User: Alexandra Moores
Date Deposited: 01 May 2020 15:55 UTC
Last Modified: 04 Jul 2023 14:31 UTC
Resource URI: (The current URI for this page, for reference purposes)

University of Kent Author Information

Moores, Alexandra.

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Blomfield, Ian C..

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