RegB/RegA, A Global Redox-Responding Two-Component System

Wu, Jiang; Bauer, Carl E.

doi:10.1007/978-0-387-78885-2_9

Cited by 54 publications

(70 citation statements)

References 63 publications

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“…This result suggested that aerobic respiration and denitrification pathways are tightly coordinated and could be under the control of a common regulator. Interestingly, Elsen et al (15) identified in B. suis the homologues of the two-component system RegB/RegA (BR0133/BR0137), also existing in B. melitensis and B. abortus (23). This led us to consider RegA to be the candidate transcriptional factor that might control various respiratory systems in B. suis.…”

Section: Resultsmentioning

confidence: 99%

RegA, the Regulator of the Two-Component System RegB/RegA of Brucella suis, Is a Controller of Both Oxidative Respiration and Denitrification Required for Chronic Infection in Mice

et al. 2013

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Adaptation to oxygen deficiency is essential for virulence and persistence of Brucella inside the host. The flexibility of this bacterium with respect to oxygen depletion is remarkable, since Brucella suis can use an oxygen-dependent transcriptional regulator of the FnrN family, two high-oxygen-affinity terminal oxidases, and a complete denitrification pathway to resist various conditions of oxygen deficiency. Moreover, our previous results suggested that oxidative respiration and denitrification can be simultaneously used by B. suis under microaerobiosis. The requirement of a functional cytochrome bd ubiquinol oxidase for nitrite reductase expression evidenced the linkage of these two pathways, and the central role of the two-component system RegB/RegA in the coordinated control of both respiratory systems was demonstrated. We propose a scheme for global regulation of B. suis respiratory pathways by the transcriptional regulator RegA, which postulates a role for the cytochrome bd ubiquinol oxidase in redox signal transmission to the histidine sensor kinase RegB. More importantly, RegA was found to be essential for B. suis persistence in vivo within oxygen-limited target organs. It is conceivable that RegA acts as a controller of numerous systems involved in the establishment of the persistent state, characteristic of chronic infections by Brucella.

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Section: Resultsmentioning

confidence: 99%

RegA, the Regulator of the Two-Component System RegB/RegA of Brucella suis, Is a Controller of Both Oxidative Respiration and Denitrification Required for Chronic Infection in Mice

et al. 2013

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“…The expression changes may be due to alteration of the redox status of the quinone pool, which would influence the phosphorylation activity of the sensor kinase RegB, known to control photosynthesis gene expression in response to alterations in the ubiquinone pool (45). These observations suggest that regulating the synthesis of the photosynthetic apparatus involves the synchronization of electron transfer activities among several components, with expression responding to different electron donors that are variable in nature.…”

Section: Discussionmentioning

confidence: 99%

Sulfide-responsive transcriptional repressor SqrR functions as a master regulator of sulfide-dependent photosynthesis

Shimizu

Shen

Fang

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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113

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Sulfide was used as an electron donor early in the evolution of photosynthesis, with many extant photosynthetic bacteria still capable of using sulfur compounds such as hydrogen sulfide (H 2 S) as a photosynthetic electron donor. Although enzymes involved in H 2 S oxidation have been characterized, mechanisms of regulation of sulfide-dependent photosynthesis have not been elucidated. In this study, we have identified a sulfide-responsive transcriptional repressor, SqrR, that functions as a master regulator of sulfide-dependent gene expression in the purple photosynthetic bacterium Rhodobacter capsulatus. SqrR has three cysteine residues, two of which, C41 and C107, are conserved in SqrR homologs from other bacteria. Analysis with liquid chromatography coupled with an electrospray-interface tandem-mass spectrometer reveals that SqrR forms an intramolecular tetrasulfide bond between C41 and C107 when incubated with the sulfur donor glutathione persulfide. SqrR is oxidized in sulfidestressed cells, and tetrasulfide-cross-linked SqrR binds more weakly to a target promoter relative to unmodified SqrR. C41S and C107S R. capsulatus SqrRs lack the ability to respond to sulfide, and constitutively repress target gene expression in cells. These results establish that SqrR is a sensor of H 2 S-derived reactive sulfur species that maintain sulfide homeostasis in this photosynthetic bacterium and reveal the mechanism of sulfide-dependent transcriptional derepression of genes involved in sulfide metabolism.sulfide sensor | photosynthesis regulation | reactive sulfur species | purple bacteria | Rhodobacter T he discovery of ∼550 deep-sea hydrothermal vents more than 30 y ago (1) has led to the theory that energy metabolism in early ancestral organisms may have arisen from deep-sea hydrothermal vents where simple inorganic molecules such as hydrogen sulfide or hydrogen gas, as well as methane, exist (2-4). Such ancient energy metabolism has been assumed to be similar to that of extant chemolithotrophs, which obtain energy from these molecules. Indeed, various chemolithoautotrophic microbes thrive in deep-sea hydrothermal vents and are capable of oxidizing sulfides, methane, and/or hydrogen gas for use as energy sources and electron donors (5). Some photosynthetic bacteria have also been isolated from deep-sea hydrothermal vents that can grow photosynthetically using sulfide as an electron donor and geothermal radiation as an energy source instead of solar radiation (6), as hypothesized for ancestral phototrophs.Many purple photosynthetic bacteria have remarkable metabolic versatility required to meet the energy demands of sulfidedependent and -independent photosynthesis as well as aerobic and anaerobic respiration. These bacteria tightly control the synthesis of their electron transfer proteins involved in each growth mode in response to a specific electron donor, oxygen tension, and light intensity (7, 8). Among these regulatory systems, oxygen-and lightsensing mechanisms have been well-studied; however, mechanisms used to sen...

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“…Homologous twocomponent systems (ActSR in Sinrohizobium meliloti, RegSR in Bradyrhizobium japonicum, PrrBA in Rhodobacter sphaeroides) can complement one another (Emmerich et al, 2000a;Elsen et al, 2004;Wu & Bauer, 2008). However, the DNA binding sites are not as well conserved among organisms compared with the aforementioned Fnr anaerobox.…”

Section: Introductionmentioning

confidence: 99%

Quinol oxidase encoded by cyoABCD in Rhizobium etli CFN42 is regulated by ActSR and is crucial for growth at low pH or low iron conditions

Lunak

Noel

2015

Microbiology

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Rhizobium etli aerobically respires with several terminal oxidases. The quinol oxidase (Cyo) encoded by cyoABCD is needed for efficient adaptation to low oxygen conditions and cyo transcription is upregulated at low oxygen. This study sought to determine how transcription of the cyo operon is regulated. The 59 sequence upstream of cyo was analysed in silico and revealed putative binding sites for ActR of the ActSR two-component regulatory system. The expression of cyo was decreased in an actSR mutant regardless of the oxygen condition. As ActSR is known to be important for growth under low pH in another rhizobial species, the effect of growth medium pH on cyo expression was tested. As the pH of the media was incrementally decreased, cyo expression gradually increased in the WT, eventually reaching ,10-fold higher levels at low pH (4.8) compared with neutral pH (7.0) conditions. This upregulation of cyo under decreasing pH conditions was eliminated in the actSR mutant. Both the actSR and cyo mutants had severe growth defects at low pH (4.8). Lastly, the actSR and cyo mutants had severe growth defects when grown in media treated with an iron chelator. Under these conditions, cyo was upregulated in the WT, whereas cyo was not induced in the actSR mutant. Altogether, the results indicated cyo expression is largely dependent on the ActSR two-component system. This study also demonstrated additional physiological roles for Cyo in R. etli CFN42, in which it is the preferred oxidase for growth under acidic and low iron conditions.

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RegB/RegA, A Global Redox-Responding Two-Component System

Cited by 54 publications

References 63 publications

RegA, the Regulator of the Two-Component System RegB/RegA of Brucella suis, Is a Controller of Both Oxidative Respiration and Denitrification Required for Chronic Infection in Mice

RegA, the Regulator of the Two-Component System RegB/RegA of Brucella suis, Is a Controller of Both Oxidative Respiration and Denitrification Required for Chronic Infection in Mice

Sulfide-responsive transcriptional repressor SqrR functions as a master regulator of sulfide-dependent photosynthesis

Quinol oxidase encoded by cyoABCD in Rhizobium etli CFN42 is regulated by ActSR and is crucial for growth at low pH or low iron conditions

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