Identification of ColR binding consensus and prediction of regulon of ColRS two-component system

Kivistik, Paula Ann; Kivi, Rait; Kivisaar, Maia; Hõrak, Rita

doi:10.1186/1471-2199-10-46

Cited by 13 publications

(38 citation statements)

References 22 publications

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“…Previous studies have shown that despite being preceded by a ColR binding site, the colR promoter is not autoregulated and this site is associated only with the regulation of PP0900, located upstream of colR [40]. However, as this data was obtained under non-inducing conditions, we tested whether the expression of the colRS operon may respond to metal excess.…”

Section: Resultsmentioning

confidence: 99%

The ColRS signal transduction system responds to the excess of external zinc, iron, manganese, and cadmium

et al. 2014

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BackgroundThe ColRS two-component system has been shown to contribute to the membrane functionality and stress tolerance of Pseudomonas putida as well as to the virulence of Pseudomonas aeruginosa and plant pathogenic Xanthomonas species. However, the conditions activating the ColRS pathway and the signal(s) sensed by ColS have remained unknown. Here we aimed to analyze the role of the ColRS system in metal tolerance of P. putida and to test whether ColS can respond to metal excess.ResultsWe show that the ColRS system is necessary for P. putida to tolerate the excess of iron and zinc, and that it also contributes to manganese and cadmium tolerance. Excess of iron, zinc, manganese or cadmium activates ColRS signaling and as a result modifies the expression of ColR-regulated genes. Our data suggest that the genes in the ColR regulon are functionally redundant, as several loci have to be deleted to observe a significant decrease in metal tolerance. Site-directed mutagenesis of ColS revealed that excess of iron and, surprisingly, also zinc are sensed by a conserved ExxE motif in ColS’s periplasmic domain. While ColS is able to sense different metals, it still discriminates between the two oxidation states of iron, specifically responding to ferric and not ferrous iron. We propose a signal perception model involving a dimeric ColS, where each monomer donates one ExxE motif for metal binding.ConclusionsSeveral transition metals are essential for living organisms in certain amounts, but toxic in excess. We show that ColRS is a sensor system which detects and responds to the excess of physiologically important metals such as zinc, iron and manganese. Thus, the ColRS system is an important factor for metal homeostasis and tolerance in P. putida.

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Section: Resultsmentioning

confidence: 99%

The ColRS signal transduction system responds to the excess of external zinc, iron, manganese, and cadmium

et al. 2014

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“…campestris (47). Thus, ColR/ColS is involved in maintaining the structural integrity and function of the outer membrane (23,24) and contributes to X. citri subsp. citri growth in planta.…”

Section: Discussionmentioning

confidence: 99%

The ColR/ColS Two-Component System Plays Multiple Roles in the Pathogenicity of the Citrus Canker Pathogen Xanthomonas citri subsp. citri

Yan

Wang

2011

J Bacteriol

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Bacterial citrus canker disease, which is caused by Xanthomonas citri subsp. citri, is one of the most devastating diseases of citrus plants. In this study, we characterized the role of the two-component regulatory system ColR/ColS in the pathogenicity of X. citri subsp. citri. colS mutants (256A10 and 421E7), colR mutants (386C6 and 417E10), and a colR colS double mutant (306DSR) all lost pathogenicity and produced no symptoms on grapefruit leaves inoculated by either pressure infiltration or the spray method. The pathogenicity defect of the colS, colR, and colR colS mutants could be complemented using the wild-type colS, colR, and colR colS genes, respectively. Mutation of colS or colR significantly reduced X. citri subsp. citri growth in planta. The ColR/ColS system also played important roles in bacterial biofilm formation in glass tubes and on leaf surfaces, lipopolysaccharide (LPS) production, catalase activity, and tolerance of environmental stress, including phenol, copper, and hydrogen peroxide. Furthermore, quantitative reverse transcription-PCR assays demonstrated that the ColR/ColS system positively regulated the expression of important virulence genes, including hrpD6, hpaF, the O-antigen LPS synthesis gene rfbC, and the catalase gene katE. Overall, our data indicate that the two-component regulatory system ColR/ColS is critical for X. citri subsp. citri virulence, growth in planta, biofilm formation, catalase activity, LPS production, and resistance to environmental stress. Xanthomonas

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“…ColRS-CprRS homologues were defined initially for P. fluorescens, in which the ColRS system is required for Pm tolerance and efficient root colonization of host plants (45,60) and subsequently for P. putida, in which this system is required for root colonization (46), specific transpositional activity (61), phenol tolerance (62,63), heavy metal tolerance (64), and protection against cell lysis in the context of metabolic responses to glucose limitation (63,65). Interestingly, oprF (PA1777) and crc (PA5332) mediate this metabolic response in P. putida (65), and ColRS also regulates the gene product of pagL (PA4661), a lipid A deacylase, in this organism (66). The present work has implicated all three of these loci in P. aeruginosa Pm resistance.…”

Section: Discussionmentioning

confidence: 99%

Polymyxin Resistance of Pseudomonas aeruginosa phoQ Mutants Is Dependent on Additional Two-Component Regulatory Systems

Gutu

Sgambati

Strasbourger

et al. 2013

Antimicrob Agents Chemother

115

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e Pseudomonas aeruginosa can develop resistance to polymyxin as a consequence of mutations in the PhoPQ regulatory system, mediated by covalent lipid A modification. Transposon mutagenesis of a polymyxin-resistant phoQ mutant defined 41 novel loci required for resistance, including two regulatory systems, ColRS and CprRS. Deletion of the colRS genes, individually or in tandem, abrogated the polymyxin resistance of a ⌬phoQ mutant, as did individual or tandem deletion of cprRS. Individual deletion of colR or colS in a ⌬phoQ mutant also suppressed 4-amino-L-arabinose addition to lipid A, consistent with the known role of this modification in polymyxin resistance. Surprisingly, tandem deletion of colRS or cprRS in the ⌬phoQ mutant or individual deletion of cprR or cprS failed to suppress 4-amino-L-arabinose addition to lipid A, indicating that this modification alone is not sufficient for PhoPQ-mediated polymyxin resistance in P. aeruginosa. Episomal expression of colRS or cprRS in tandem or of cprR individually complemented the Pm resistance phenotype in the ⌬phoQ mutant, while episomal expression of colR, colS, or cprS individually did not. Highly polymyxin-resistant phoQ mutants of P. aeruginosa isolated from polymyxin-treated cystic fibrosis patients harbored mutant alleles of colRS and cprS; when expressed in a ⌬phoQ background, these mutant alleles enhanced polymyxin resistance. These results define ColRS and CprRS as two-component systems regulating polymyxin resistance in P. aeruginosa, indicate that addition of 4-amino-L-arabinose to lipid A is not the only PhoPQ-regulated biochemical mechanism required for resistance, and demonstrate that colRS and cprS mutations can contribute to high-level clinical resistance.

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Identification of ColR binding consensus and prediction of regulon of ColRS two-component system

Cited by 13 publications

References 22 publications

The ColRS signal transduction system responds to the excess of external zinc, iron, manganese, and cadmium

The ColRS signal transduction system responds to the excess of external zinc, iron, manganese, and cadmium

The ColR/ColS Two-Component System Plays Multiple Roles in the Pathogenicity of the Citrus Canker Pathogen Xanthomonas citri subsp. citri

Polymyxin Resistance of Pseudomonas aeruginosa phoQ Mutants Is Dependent on Additional Two-Component Regulatory Systems

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