Two-component regulators control hilA expression by controlling fimZ and hilE expression within Salmonella enterica serovar Typhimurium

M Aaron Baxter; Bradley D Jones

doi:10.1128/IAI.02506-14

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Two-component regulators control hilA expression by controlling fimZ and hilE expression within Salmonella enterica serovar Typhimurium

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Two-component regulators control hilA expression by controlling fimZ and hilE expression within Salmonella enterica serovar Typhimurium

M Aaron Baxter and Bradley D Jones

Infection and immunity, Vol.83(3), pp.978-985

03/2015

DOI: 10.1128/IAI.02506-14

PMCID: PMC4333451

PMID: 25547794

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Abstract

Salmonellae initiate disease through the invasion of host cells within the intestine. This ability to invade requires the coordinated action of numerous genes, many of which are found within Salmonella pathogenicity island 1 (SPI-1). The key to this process is the ability of the bacteria to respond to the environment, thereby upregulating the necessary genes under optimal conditions. Central to the control of SPI-1 is the transcriptional activator hilA. Work has identified at least 10 different activators and 8 different repressors responsible for the control of hilA. We have previously shown that hilE is a Salmonella-specific negative regulator that is able to repress hilA expression and invasion. Additionally, fimZ, a transcriptional activator responsible for the expression of type I fimbriae as well as flagellar genes, has also been implicated in this process. fimZ is homologous to response regulators from other two-component regulatory systems, although a sensor for the system has not been identified. The phoPQ and phoBR regulons are both two-component systems that negatively affect hilA expression, although the mechanism of action has not been determined. Our results show that PhoBR is capable of inducing fimZ expression, whereas PhoPQ does not affect fimZ expression but does upregulate hilE in an FimZ-dependent manner. Therefore, phosphate (sensed by PhoBR) and magnesium (sensed by PhoPQ) levels are important in controlling hilA expression levels when Salmonella is in the intestinal environment.

Promoter Regions, Genetic

Salmonella typhimurium - genetics

Salmonella typhimurium - pathogenicity

Bacterial Proteins - genetics

Genomic Islands

Repressor Proteins - genetics

Magnesium - metabolism

Fimbriae, Bacterial - genetics

Salmonella typhimurium - metabolism

Regulon

Phosphates - metabolism

Trans-Activators - genetics

Bacterial Proteins - metabolism

Trans-Activators - metabolism

Transcription, Genetic

Gene Expression Regulation, Bacterial

Repressor Proteins - metabolism

Fimbriae, Bacterial - metabolism

Details

Title: Subtitle: Two-component regulators control hilA expression by controlling fimZ and hilE expression within Salmonella enterica serovar Typhimurium
Creators: M Aaron Baxter - Genetics Program, University of Iowa Roy J. and Lucille A. Carver School of Medicine, Iowa City, Iowa, USA Department of Biomedical Sciences, Grand Valley State University, Allendale, Michigan, USA
Bradley D Jones - Genetics Program, University of Iowa Roy J. and Lucille A. Carver School of Medicine, Iowa City, Iowa, USA Department of Microbiology, University of Iowa Roy J. and Lucille A. Carver School of Medicine, Iowa City, Iowa, USA bradley-jones@uiowa.edu
Resource Type: Journal article
Publication Details: Infection and immunity, Vol.83(3), pp.978-985
DOI: 10.1128/IAI.02506-14
PMID: 25547794
PMCID: PMC4333451
ISSN: 0019-9567
eISSN: 1098-5522
Grant note: 2P01 AI044642 / NIAID NIH HHS P01 AI044642 / NIAID NIH HHS
Language: English
Date published: 03/2015
Academic Unit: Microbiology and Immunology
Record Identifier: 9984083267502771

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