scholarly journals Involvement of Nitrogen Regulation in Bacillus subtilis degU Expression

2008 ◽  
Vol 190 (15) ◽  
pp. 5162-5171 ◽  
Author(s):  
Ayako Yasumura ◽  
Sadanobu Abe ◽  
Teruo Tanaka

ABSTRACT Bacillus subtilis DegS-DegU belongs to a bacterial two-component system that controls many processes, including the production of exocellular proteases and competence development. It was found that when the glutamine synthetase gene glnA, which is involved in nitrogen regulation, was disrupted, the expression of the response regulator degU gene was increased. Deletion analysis and 5′-end mapping of the degU transcripts showed that the increase was caused by induction of a promoter (P2) located before the degU gene. Disruption of tnrA, a global regulator of nitrogen regulation, eliminated the P2 promoter induction by the glnA mutation. The fact that the P2 promoter is under nitrogen regulation was demonstrated by an increase in P2 expression with nitrogen-limited growth. It was also found by primer extension analysis that degU was transcribed by another promoter, P3, that is located downstream of P2. Efficient expression of P3 was dependent on phosphorylated DegU, as inactivation of the sensor kinase gene, degS, resulted in the loss of degU expression, although less efficient stimulation of degU expression was also observed with an enhanced level of DegU in a degS-deficient mutant. The promoter located upstream of the degSU operon, designated the P1 promoter here, was insensitive to glnA and degU mutations. These results suggest that degU expression is controlled by the three promoters under different growth conditions.

2004 ◽  
Vol 186 (13) ◽  
pp. 4262-4275 ◽  
Author(s):  
Salbi Paul ◽  
Stephanie Birkey ◽  
Wei Liu ◽  
F. Marion Hulett

ABSTRACT The phoPR operon encodes a response regulator, PhoP, and a histidine kinase, PhoR, which activate or repress genes of the Bacillus subtilis Pho regulon in response to an extracellular phosphate deficiency. Induction of phoPR upon phosphate starvation required activity of both PhoP and PhoR, suggesting autoregulation of the operon, a suggestion that is supported here by PhoP footprinting on the phoPR promoter. Primer extension analyses, using RNA from JH642 or isogenic sigE or sigB mutants isolated at different stages of growth and/or under different growth conditions, suggested that expression of the phoPR operon represents the sum of five promoters, each responding to a specific growth phase and environmental controls. The temporal expression of the phoPR promoters was investigated using in vitro transcription assays with RNA polymerase holoenzyme isolated at different stages of Pho induction, from JH642 or isogenic sigE or sigB mutants. In vitro transcription studies using reconstituted EσA, EσB, and EσE holoenzymes identified PA4 and PA3 as EσA promoters and PE2 as an EσE promoter. Phosphorylated PhoP (PhoP∼P) enhanced transcription from each of these promoters. EσB was sufficient for in vitro transcription of the PB1 promoter. P5 was active only in a sigB mutant strain. These studies are the first to report a role for PhoP∼P in activation of promoters that also have activity in the absence of Pho regulon induction and an activation role for PhoP∼P at an EσE promoter. Information concerning PB1 and P5 creates a basis for further exploration of the regulatory coordination or overlap of the PhoPR and SigB regulons during phosphate starvation.


1999 ◽  
Vol 181 (22) ◽  
pp. 7087-7097 ◽  
Author(s):  
Michiko M. Nakano ◽  
Yi Zhu ◽  
Koki Haga ◽  
Hirofumi Yoshikawa ◽  
Abraham L. Sonenshein ◽  
...  

ABSTRACT The Bacillus subtilis ResD-ResE two-component signal transduction system is essential for aerobic and anaerobic respiration. A spontaneous suppressor mutant that expresses ResD-controlled genes and grows anaerobically in the absence of the ResE histidine kinase was isolated. In addition, aerobic expression of ResD-controlled genes in the suppressed strain was constitutive and occurred at a much higher level than that observed in the wild-type strain. The suppressing mutation, which mapped to pgk, the gene encoding 3-phosphoglycerate kinase, failed to suppress a resDmutation, suggesting that the suppressing mutation creates a pathway for phosphorylation of the response regulator, ResD, which is independent of the cognate sensor kinase, ResE. The pgk-1mutant exhibited very low but measurable 3-phosphoglycerate kinase activity compared to the wild-type strain. The results suggest that accumulation of a glycolytic intermediate, probably 1,3-diphosphoglycerate, is responsible for the observed effect of thepgk-1 mutation on anaerobiosis of resE mutant cells.


2005 ◽  
Vol 187 (9) ◽  
pp. 3267-3272 ◽  
Author(s):  
Gabriela R. Peña-Sandoval ◽  
Ohsuk Kwon ◽  
Dimitris Georgellis

ABSTRACT The Arc two-component system, comprising the ArcB sensor kinase and the ArcA response regulator, modulates the expression of numerous genes in response to the respiratory conditions of growth. Under anoxic growth conditions, ArcB autophosphorylates and transphosphorylates ArcA, which in turn represses or activates its target operons. Under aerobic growth conditions, phosphorylated ArcA (ArcA-P) dephosphorylates and its transcriptional regulation is released. The dephosphorylation of ArcA-P has been shown to occur, at least in vitro, via an ArcAAsp54-P → ArcBHis717-P → ArcBAsp576-P → Pi reverse phosphorelay. In this study, the physiological significance of this pathway was assessed. The results demonstrate that the receiver and phosphotransfer domains of the tripartite sensor kinase ArcB are necessary and sufficient for efficient ArcA-P dephosphorylation in vivo.


2008 ◽  
Vol 190 (16) ◽  
pp. 5720-5728 ◽  
Author(s):  
Cinzia Calvio ◽  
Cecilia Osera ◽  
Giuseppe Amati ◽  
Alessandro Galizzi

ABSTRACT We demonstrate that transcription of the gene swrAA, required for swarming migration in Bacillus subtilis, is driven by two promoters: a sigD-dependent promoter and a putative sigA-dependent promoter, which is inactive during growth in liquid Luria-Bertani medium and becomes active in the presence of the phosphorylated form of the response regulator DegU or on semisolid surfaces. Since sigD transcription is enhanced by SwrAA, this finding reveals that swrA expression is controlled by a positive feedback loop. We also demonstrate that the positive action of SwrAA in swimming and swarming motility is prevented in strains carrying a deletion of the two-component system degS-degU and that this effect is independent of swrAA transcription. Therefore, both DegU and SwrAA must be present to achieve full motility in B. subtilis.


2004 ◽  
Vol 186 (7) ◽  
pp. 2085-2090 ◽  
Author(s):  
Claudia Rodriguez ◽  
Ohsuk Kwon ◽  
Dimitris Georgellis

ABSTRACT The Arc two-component system, comprising the ArcB sensor kinase and the ArcA response regulator, modulates the expression of numerous genes in response to the respiratory growth conditions. Under anoxic growth conditions ArcB autophosphorylates and transphosphorylates ArcA, which in turn represses or activates its target operons. The anaerobic metabolite d-lactate has been shown to stimulate the in vitro autophosphorylating activity of ArcB. In this study, the in vivo effect of d-lactate on the kinase activity of ArcB was assessed. The results demonstrate that d-lactate does not act as a direct signal for activation of ArcB, as previously proposed, but acts as a physiologically significant effector that amplifies ArcB kinase activity.


2017 ◽  
Vol 199 (22) ◽  
Author(s):  
Qing Chen ◽  
Victoria Ng ◽  
Jason M. Warfel ◽  
Tod J. Merkel ◽  
Scott Stibitz

ABSTRACT The two-component response regulator RisA, encoded by open reading frame BP3554 in the Bordetella pertussis Tohama I genomic sequence, is a known activator of vrg genes, a set of genes whose expression is increased under the same environmental conditions (known as modulation) that result in repression of the bvgAS virulence regulon. Here we demonstrate that RisA is phosphorylated in vivo and that RisA phosphorylation is required for activation of vrg genes. An adjacent histidine kinase gene, risS, is truncated by frameshift mutation in B. pertussis but not in Bordetella bronchiseptica or Bordetella parapertussis. Neither deletion of risS′ or bvgAS nor phenotypic modulation with MgSO4 affected levels of phosphorylated RisA (RisA∼P) in B. pertussis. However, RisA phosphorylation did require the histidine kinase encoded by BP3223, here named RisK (cognate histidine kinase of RisA). RisK was also required for expression of the vrg genes. This requirement could be obviated by the introduction of the phosphorylation-mimicking RisAD60E mutant, indicating that an active conformation of RisA, but not phosphorylation per se, is crucial for vrg activation. Interestingly, expression of vrg genes is still modulated by MgSO4 in cells harboring the RisAD60E mutation, suggesting that the activated RisA senses additional signals to control vrg expression in response to environmental stimuli. IMPORTANCE In B. pertussis, the BvgAS two-component system activates the expression of virulence genes by binding of BvgA∼P to their promoters. Expression of the reciprocally regulated vrg genes requires RisA and is also repressed by the Bvg-activated BvgR. RisA is an OmpR-like response regulator, but RisA phosphorylation was not expected because the gene for its presumed, cooperonic, histidine kinase is inactivated by mutation. In this study, we demonstrate phosphorylation of RisA in vivo by a noncooperonic histidine kinase. We also show that RisA phosphorylation is necessary but not sufficient for vrg activation but, importantly, is not affected by BvgAS status. Instead, we propose that vrg expression is controlled by BvgAS through its regulation of BvgR, a cyclic di-GMP (c-di-GMP) phosphodiesterase.


2009 ◽  
Vol 191 (15) ◽  
pp. 4732-4749 ◽  
Author(s):  
Jennifer I. Handford ◽  
Bérengère Ize ◽  
Grant Buchanan ◽  
Gareth P. Butland ◽  
Jack Greenblatt ◽  
...  

ABSTRACT The yjeE, yeaZ, and ygjD genes are highly conserved in the genomes of eubacteria, and ygjD orthologs are also found throughout the Archaea and eukaryotes. In this study, we have constructed conditional expression strains for each of these genes in the model organism Escherichia coli K12. We show that each gene is essential for the viability of E. coli under laboratory growth conditions. Growth of the conditional strains under nonpermissive conditions results in dramatic changes in cell ultrastructure. Deliberate repression of the expression of yeaZ results in cells with highly condensed nucleoids, while repression of yjeE and ygjD expression results in at least a proportion of very enlarged cells with an unusual peripheral distribution of DNA. Each of the three conditional expression strains can be complemented by multicopy clones harboring the rstA gene, which encodes a two-component-system response regulator, strongly suggesting that these proteins are involved in the same essential cellular pathway. The results of bacterial two-hybrid experiments show that YeaZ can interact with both YjeE and YgjD but that YgjD is the preferred interaction partner. The results of in vitro experiments indicate that YeaZ mediates the proteolysis of YgjD, suggesting that YeaZ and YjeE act as regulators to control the activity of this protein. Our results are consistent with these proteins forming a link between DNA metabolism and cell division.


2003 ◽  
Vol 185 (3) ◽  
pp. 843-853 ◽  
Author(s):  
Anna-Karin Pernestig ◽  
Dimitris Georgellis ◽  
Tony Romeo ◽  
Kazushi Suzuki ◽  
Henrik Tomenius ◽  
...  

ABSTRACT The Escherichia coli BarA and UvrY proteins were recently demonstrated to constitute a novel two-component system, although its function has remained largely elusive. Here we show that mutations in the sensor kinase gene, barA, or the response regulator gene, uvrY, in uropathogenic E. coli drastically affect survival in long-term competition cultures. Using media with gluconeogenic carbon sources, the mutants have a clear growth advantage when competing with the wild type, but using media with carbon sources feeding into the glycolysis leads to a clear growth advantage for the wild type. Results from competitions with mutants in the carbon storage regulation system, CsrA/B, known to be a master switch between glycolysis and gluconeogenesis, led us to propose that the BarA-UvrY two-component system controls the Csr system. Taking these results together, we propose the BarA-UvrY two-component system is crucial for efficient adaptation between different metabolic pathways, an essential function for adaptation to a new environment.


Microbiology ◽  
2005 ◽  
Vol 151 (6) ◽  
pp. 1751-1759 ◽  
Author(s):  
Mark A. Strauch ◽  
Petek Ballar ◽  
Austin J. Rowshan ◽  
Katherine L. Zoller

The Bacillus subtilis AbrB protein is a DNA-binding global regulator of a plethora of functions that are expressed during the transition from exponential growth to stationary phase and under suboptimal growth conditions. AbrB orthologues have been identified in a variety of prokaryotic organisms, notably in all species of Bacillus, Clostridium and Listeria that have been examined. Based on amino acid sequence identity in the N-terminal domains of the orthologues from B. subtilis and Bacillus anthracis, it was predicted that the proteins might display identical DNA-binding specificities. The binding of purified B. anthracis AbrB (AbrBBA) and purified B. subtilis AbrB (AbrBBS) at DNA targets of B. subtilis, B. anthracis and a synthetic origin was compared. In all cases examined, DNA-binding specificity was identical as judged by DNase I footprinting. In B. subtilis cells, the B. anthracis promoters from the atxA and abrB genes were regulated by AbrBBS, and the B. subtilis promoter from the yxbB operon was regulated by AbrBBA.


2005 ◽  
Vol 71 (9) ◽  
pp. 5411-5419 ◽  
Author(s):  
Livia Leoni ◽  
Giordano Rampioni ◽  
Valeria Di Stefano ◽  
Elisabetta Zennaro

ABSTRACT In Pseudomonas fluorescens ST, the promoter of the styrene catabolic operon, PstyA, is induced by styrene and repressed by the addition of preferred carbon sources. PstyA is regulated by the StyS/StyR two-component system. The integration host factor (IHF) also plays a positive role in PstyA regulation. Three distinct StyR binding sites, which have different affinities for this response regulator, have been characterized on PstyA. The high-affinity StyR binding site (STY2) is necessary for promoter activity. The DNA region upstream of STY2 contains a lower-affinity StyR binding site, STY1, that partially overlaps the IHF binding site. Deletion of this region, designated URE (upstream regulatory element), has a dual effect on the PstyA promoter, decreasing the styrene-dependent activity and partially relieving the glucose repression. The lowest-affinity StyR binding site (STY3) is located downstream of the transcription start point. Deletion of the URE region and inactivation of the STY3 site completely abolished glucose-mediated repression of PstyA. In the proposed model StyR can act either as an activator or as a repressor, depending on which sites it occupies in the different growth conditions. We suggest that the cellular levels of phosphorylated StyR, as determined by StyS sensor kinase activity, and the interplay of this molecule with IHF modulate the activity of the promoter in different growth conditions.


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