title: Phosphate starvation relayed by PhoB activates the expression of the Pseudomonas aeruginosa σvreI ECF factor and its target genes.
abstract: The cell-surface signalling (CSS) system represents an important regulatory mechanism by which Gram-negative bacteria respond to the environment. Gene regulation by CSS systems is particularly present and important in the opportunistic human pathogen Pseudomonas aeruginosa. In this bacterium, these mechanisms regulate mainly the uptake of iron, but also virulence functions. The latter is the case for the P. aeruginosa PUMA3 CSS system formed by the putative VreA receptor, the σ(VreI) extracytoplasmic function sigma factor and the VreR anti-sigma factor. A role for this system in P. aeruginosa virulence has been demonstrated previously. However, the conditions under which this system is expressed and activated have not been elucidated so far. In this work, we have identified and characterized the global regulatory cascade activating the expression of the PUMA3 system. We show that the PhoB transcriptional regulator, part of the PhoB-PhoR two-component signalling system, can sense a limitation of inorganic phosphate to turn on the expression of the vreA, vreI and vreR genes, which constitute an operon. Upon expression of these genes in this condition, σ(VreI) factor mediates transcription of most, but not all, of the previously identified σ(VreI)-regulated genes. Indeed, we found new σ(VreI)-targeted genes and we show that σ(VreI)-regulon genes are all located immediately downstream to the vreAIR gene cluster.
authors: UMR7255, CNRS - Aix Marseille University, 31 Chemin Joseph Aiguier, 13402 Marseille, France.
authors: Laura M
authors: LM
authors: Faure
authors: Department of Environmental Protection, Estación Experimental del Zaidín-CSIC, 18008 Granada, Spain.
authors: María A
authors: MA
authors: Llamas
authors: Section of Molecular Microbiology, Department of Molecular Cell Biology, VU University, 1081 HV Amsterdam, The Netherlands.|Department of Environmental Protection, Estación Experimental del Zaidín-CSIC, 18008 Granada, Spain.
authors: Karlijn C
authors: KC
authors: Bastiaansen
authors: UMR7255, CNRS - Aix Marseille University, 31 Chemin Joseph Aiguier, 13402 Marseille, France.
authors: Sophie
authors: S
authors: de Bentzmann
authors: UMR7255, CNRS - Aix Marseille University, 31 Chemin Joseph Aiguier, 13402 Marseille, France.
authors: Sarah
authors: S
authors: Bigot
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D006801:Humans; D009876:Operon; D010710:Phosphates / Q000378:metabolism / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D001426:Bacterial Proteins; D010710:Phosphates; D012808:Sigma Factor; C061278:PhoB protein, Bacteria