σ(N) -Dependent Control of Acid Resistance and the Locus of Enterocyte Effacement in Enterohemorrhagic Escherichia Coli is Activated by Acetyl Phosphate in a Manner Requiring Flagellar Regulator FlhDC and the σ(S) Antagonist FliZ

Authors

Avishek Mitra, University of South Florida
Pamela A. Fay, University of South Florida
Khoury W. Vendura, University of South Florida
Zimrisha Alla, University of South Florida
Ronan K. Carroll, University of South Florida
Lindsey N. Shaw, University of South Florida
James T. Riordan, University of South Florida

Document Type

Article

Publication Date

8-2014

Keywords

Carboxylic Acids, Drug Tolerance, Enterohemorrhagic Escherichia coli, Escherichia coli Proteins, Gene Deletion, Gene Expression Regulation, Bacterial, Glutamates, Organophosphates, Phosphoproteins, Repressor Proteins, Sigma Factor, Trans-Activators, Transcriptional Activation

Digital Object Identifier (DOI)

http://dx.doi.org/10.1002/mbo3.183

Abstract

In enterohemorrhagic Escherichia coli (EHEC), sigma factor N (σ^N) regulates glutamate-dependent acid resistance (GDAR) and the locus of enterocyte effacement (LEE); discrete genetic systems that are required for transmission and virulence of this intestinal pathogen. Regulation of these systems requires nitrogen regulatory protein C, NtrC, and is a consequence of NtrC-σ^N-dependent reduction in the activity of sigma factor S (σ^S). This study elucidates pathway components and stimuli for σ^N-directed regulation of GDAR and the LEE in EHEC. Deletion of fliZ, the product of which reduces σ^S activity, phenocopied rpoN (σ^N) and ntrC null strains for GDAR and LEE control, acid resistance, and adherence. Upregulation of fliZ by NtrC-σ^N was shown to be indirect and required an intact flagellar regulator flhDC. Activation of flhDC by NtrC-σ^N and FlhDC-dependent regulation of GDAR and the LEE was dependent on σ^N-promoter flhD_P2, and a newly described NtrC upstream activator sequence. Addition of ammonium chloride significantly altered expression of GDAR and LEE, acid resistance, and adherence, independently of rpoN, ntrC, and the NtrC sensor kinase, ntrB. Altering the availability of NtrC phosphodonor acetyl phosphate by growth without glucose, with acetate addition, or by deletion of acetate kinase ackA, abrogated NtrC-σ^N-dependent control of flhDC, fliZ, GDAR, and the LEE.

Rights Information

This work is licensed under a Creative Commons Attribution 3.0 License.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

MicrobiologyOpen, v. 3, issue 4, p. 497-512

Scholar Commons Citation

Mitra, Avishek; Fay, Pamela A.; Vendura, Khoury W.; Alla, Zimrisha; Carroll, Ronan K.; Shaw, Lindsey N.; and Riordan, James T., "σ(N) -Dependent Control of Acid Resistance and the Locus of Enterocyte Effacement in Enterohemorrhagic Escherichia Coli is Activated by Acetyl Phosphate in a Manner Requiring Flagellar Regulator FlhDC and the σ(S) Antagonist FliZ" (2014). Molecular Biosciences Faculty Publications. 7.
https://digitalcommons.usf.edu/bcm_facpub/7