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Transcriptional regulation of the phoPR operon in Bacillus subtilis.

Prágai, Zoltán, Allenby, Nick, O'Connor, Nicola, Dubrac, Sarah, Rapoport, Georges, Msadek, Tarek and Harwood, Colin R. (2004) Transcriptional regulation of the phoPR operon in Bacillus subtilis. Journal of bacteriology, 186 (4). pp. 1182-1190. ISSN 0021-9193

Item Type: Article


When Bacillus subtilis is subjected to phosphate starvation, the Pho regulon is activated by the PhoP-PhoR two-component signal transduction system to elicit specific responses to this nutrient limitation. The response regulator, PhoP, and its cognate histidine sensor kinase, PhoR, are encoded by the phoPR operon that is transcribed as a 2.7-kb bicistronic mRNA. The phoPR operon is transcribed from two σA-dependent promoters, P1 and P2. Under conditions where the Pho regulon was not induced (i.e., phosphate-replete conditions or phoR-null mutant), a low level of phoPR transcription was detected only from promoter P1. During phosphate starvation-induced transition from exponential to stationary phase, the expression of the phoPR operon was up-regulated in a phosphorylated PhoP (PhoP∼P)-dependent manner; in addition to P1, the P2 promoter becomes active. In vitro gel shift assays and DNase I footprinting experiments showed that both PhoP and PhoP∼P could bind to the control region of the phoPR operon. The data indicate that while low-level constitutive expression of phoPR is required under phosphate-replete conditions for signal perception and transduction, autoinduction is required to provide sufficient PhoP∼P to induce other members of the Pho regulon. The extent to which promoters P1 and P2 are activated appears to be influenced by the presence of other sigma factors, possibly the result of sigma factor competition. For example, phoPR is hyperinduced in a sigB mutant and, later in stationary phase, in sigH, sigF, and sigE mutants. The data point to a complex regulatory network in which other stress responses and post-exponential-phase processes influence the expression of phoPR and, thereby, the magnitude of the Pho regulon response.

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Depositing User: Nick Allenby


Item ID: 16431
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ISSN: 0021-9193
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ORCID for Nick Allenby: ORCID iD

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Date Deposited: 13 Sep 2023 11:39
Last Modified: 13 Sep 2023 11:56


Author: Nick Allenby ORCID iD
Author: Zoltán Prágai
Author: Nicola O'Connor
Author: Sarah Dubrac
Author: Georges Rapoport
Author: Tarek Msadek
Author: Colin R. Harwood

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Faculty of Health Sciences and Wellbeing


Sciences > Biomedical Sciences

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