RovA is autoregulated and antagonizes H‐NS‐mediated silencing of invasin and <i>rovA</i> expression in <i>Yersinia pseudotuberculosis</i>

Heroven, Ann Kathrin; Nagel, Geraldine; Tran, Hien J.; Parr, Susanne; Dersch, Petra

doi:10.1111/j.1365-2958.2004.04162.x

Cited by 120 publications

(230 citation statements)

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“…The data presented for SlyA and its homologue, RovA from Yersinia, suggest that the regulatory proteins of this family may positively regulate genes by acting as derepressors (Heroven et al, 2004;Wyborn et al, 2004). For example, E. coli hlyE (also known as clyA and sheA), which encodes a novel pore-forming toxin, is regulated positively by the global transcriptional factors FNR (fumarate and nitrate reduction) and CRP (cAMP receptor protein) and by SlyA, and negatively by the nucleoid-structuring protein H-NS (Wyborn et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Identification of amino acid residues of Salmonella SlyA that are critical for transcriptional regulation

Okada

Takeda‐Shitaka

et al. 2007

Microbiology

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The type III secretion system encoded by Salmonella pathogenicity island 2 (SPI-2) is essential for the intracellular survival and replication of Salmonella enterica. The expression of SPI-2 genes is dependent on a two-component regulatory system, SsrA (SpiR)/SsrB, encoded in the SPI-2 region. This paper shows that SlyA regulates transcription of the sensor kinase SsrA by binding to the ssrA promoter, indicating that SlyA is directly involved in the regulation of SPI-2 gene expression. A structure model of the SlyA dimer in complex with DNA was constructed. The model of SlyA indicated that its structure is very similar to that of other MarR family proteins. Based on this model, site-directed mutagenesis of residues located in the winged-helix region required for DNA binding and in the a-helices of the N-terminal and C-terminal regions required for dimerization of the SlyA protein was performed to identify the residues that are critical for SlyA function. Nine mutants of SlyA with single substitutions were unable to activate ssrA transcription in vivo. These mutant SlyA proteins revealed that the residues Leu-63, Val-64, Arg-65, Leu-67, Leu-70, Arg-86 and Lys-88 within the winged-helix region are required for DNA binding, and residues Leu-12 and Leu-126 within the a-helices of the N-terminal and C-terminal regions are required for efficient dimer formation. A Salmonella slyA mutant strain carrying a plasmid expressing SlyA derivatives containing mutations at these amino acid positions did not exhibit restored SlyA function in infected HeLa cells, thereby confirming the structural and functional relationships of the SlyA protein. INTRODUCTIONSalmonella enterica, a facultative intracellular pathogen, can replicate within macrophages. The intracellular survival of S. enterica serovar Typhimurium requires a number of virulence-associated proteins encoded in Salmonella pathogenicity island 2 (SPI-2) on the bacterial chromosome (Cirillo et al., 1998;Hensel, 2000;Ochman et al., 1996;Shea et al., 1996). SPI-2 encodes a two-component regulatory system, structural components of a type III secretion system (TTSS), effector proteins and chaperones, which mediate the secretion of the effectors (Cirillo et al., 1998;Hensel et al., 1998;Ochman et al., 1996;Shea et al., 1996). In infected macrophages, Salmonella replicates within a membranebound compartment (Salmonella-containing vacuole, SCV) inside the host cells (Steele-Mortimer et al., 2002). Intracellular activation of SPI-2 function is essential for SCV maturation along the phagolysosomal fusion pathway, which is responsible for the inhibition of bacterial degradation in phagolysosomes. The SPI-2 TTSS functions to export effector proteins across the SCV membrane and into the cytosol of host cells, resulting in the prevention of the recruitment of NADPH oxidase to the SCV (Gallois et al., 2001;Vazquez-Torres et al., 2000), as well as leading to the rearrangement of cellular microfilaments (Meresse et al., 2001;Miao et al., 2002) and microtubule networks (Brumell et al., 20...

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Section: Discussionmentioning

confidence: 99%

Identification of amino acid residues of Salmonella SlyA that are critical for transcriptional regulation

Okada

Takeda‐Shitaka

et al. 2007

Microbiology

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“…SlyA is related to wingedhelix proteins such as MarR (E. coli), RovA (Yersinia) and PecS (Erwinia) and it has been studied in Salmonella and E. coli, where it controls the expression of a large group of genes (Cathelyn et al, 2006(Cathelyn et al, , 2007Ellison & Miller, 2006a;Heroven et al, 2004;Revell & Miller, 2000;Reverchon et al, 1994;Wilkinson & Grove, 2006). This contrasts with other anti-silencers, such as VirB, that act at far fewer promoters.…”

Section: H-ns Antagonism By Slya-like Proteinsmentioning

confidence: 99%

Anti-silencing: overcoming H-NS-mediated repression of transcription in Gram-negative enteric bacteria

2008

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“…The Nylon membrane was blocked for 30 min in blocking buffer (0.1 M maleic acid at pH 7.5, 0.15 M NaCl) with 1% blocking reagent (Roche) and incubated with 1:10000 diluted anti-DIG antibody (Roche) in blocking buffer for 1 h. Digested DNA fragments were visualized using CDP-Star (Roche) in detection buffer (0.1 M Tris-HCl at pH 9.5, 0.15 M NaCl). Protected regions were identified by comparison with a DNA sequence ladder generated with the same DIG-labeled primer as used for amplification of the DNA fragment by PCR (Heroven et al 2004). …”

Section: Protein-dna Interaction Assaysmentioning

confidence: 99%

A two-component phosphotransfer network involving ArcB, ArcA, and RssB coordinates synthesis and proteolysis of σ^S (RpoS) in E. coli

Mika¹,

Hengge²

2005

Genes Dev.

170

150

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The general stress factor S (RpoS) in Escherichia coli is controlled at the levels of transcription, translation, and proteolysis. Here we demonstrate that the phosphorylated response regulator ArcA is a direct repressor of rpoS transcription that binds to two sites flanking the major rpoS promoter, with the upstream site overlapping an activating cAMP-CRP-binding site. The histidine sensor kinase ArcB not only phosphorylates ArcA, but also the S proteolytic targeting factor RssB, and thereby stimulates S proteolysis. Thus, ArcB/ArcA/RssB constitute a branched "three-component system", which coordinates rpoS transcription and S proteolysis and thereby maintains low S levels in rapidly growing cells. We suggest that the redox state of the quinones, which controls autophosphorylation of ArcB, not only monitors oxygen but also energy supply, and we show that the ArcB/ArcA/RssB system is involved in S induction during entry into starvation conditions. Moreover, this induction is enhanced by a positive feedback that involves S -dependent induction of ArcA, which further reduces S proteolysis, probably by competing with RssB for residual phosphorylation by ArcB. [Keywords: Histidine sensor kinase; response regulator; RNA polymerase; RpoS; starvation; stress] Controlled proteolysis of key regulatory factors in response to cellular and environmental signals plays a crucial role both in eukaryotic and prokaryotic cells. One of the most prominent prokaryotic examples is the degradation of the S (RpoS) subunit of RNA polymerase (RNAP) in rapidly growing Escherichia coli cells, which is inhibited in response to several stress conditions: e.g., starvation, hyperosmotic shift, or pH downshift (for a summary of S regulation, see Hengge-Aronis 2002). This results in a rapid increase of the cellular concentration of S , which competes with the vegetative subunit 70 , and thereby induces the general stress response (Hengge-Aronis 2000), which affects the expression of ∼10% of the E. coli genes (Weber et al. 2005). In parallel, rpoS transcription can be enhanced in response to poor nutritional conditions and reduced growth rates (Hengge-Aronis 2002). In addition, the efficiency of rpoS mRNA translation is controlled by various stress-sensing mechanisms that involve small regulatory RNAs and the Hfq protein (Repoila et al. 2003). Whether these levels of control operate independently and additively or are somehow coordinated, is still an open question.The present study started from the question of how S proteolysis is regulated. S degradation requires the complex ATP-dependent ClpXP protease as well as the response regulator RssB, which, in its phosphorylated form, binds to S (thereby exposing a ClpX-binding site in S ), delivers S to ClpXP, and is released from the complex (Becker et al. 1999;Klauck et al. 2001;Zhou et al. 2001). Thus, RssB acts as a proteolytic recognition or targeting factor for S . This process is regulated by various mechanisms that affect specific substrate, i.e., S recognition, and can integrate different ...

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RovA is autoregulated and antagonizes H‐NS‐mediated silencing of invasin and rovA expression in Yersinia pseudotuberculosis

Cited by 120 publications

References 50 publications

Identification of amino acid residues of Salmonella SlyA that are critical for transcriptional regulation

Identification of amino acid residues of Salmonella SlyA that are critical for transcriptional regulation

Anti-silencing: overcoming H-NS-mediated repression of transcription in Gram-negative enteric bacteria

A two-component phosphotransfer network involving ArcB, ArcA, and RssB coordinates synthesis and proteolysis of σ^S (RpoS) in E. coli

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RovA is autoregulated and antagonizes H‐NS‐mediated silencing of invasin and rovA expression in Yersinia pseudotuberculosis

Cited by 120 publications

References 50 publications

Identification of amino acid residues of Salmonella SlyA that are critical for transcriptional regulation

Identification of amino acid residues of Salmonella SlyA that are critical for transcriptional regulation

Anti-silencing: overcoming H-NS-mediated repression of transcription in Gram-negative enteric bacteria

A two-component phosphotransfer network involving ArcB, ArcA, and RssB coordinates synthesis and proteolysis of σS (RpoS) in E. coli

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Product

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A two-component phosphotransfer network involving ArcB, ArcA, and RssB coordinates synthesis and proteolysis of σ^S (RpoS) in E. coli