title: Function of the bacteriophytochrome BphP in the RpoS/Las quorum-sensing network of Pseudomonas aeruginosa.
abstract: The bacterial phytochrome of Pseudomonas aeruginosa (PaBphP) is an in vitro-active red/far-red light sensor histidine kinase of a two-component regulatory system. Despite solid biochemical data, its function in this heterotrophic, opportunistic pathogen is still unknown. Previous studies established that the genes encoding the two necessary phytochrome components BphO, a chromophore-producing haem oxygenase, and BphP, the apo-phytochrome, are co-transcribed in a bicistronic operon. Transcription has been shown to be induced in the stationary phase and to be dependent on the alternative sigma factor RpoS. Here we show an additional regulation of bphP expression through the quorum-sensing (QS) regulator LasR. This regulation is also reflected in a combination of expression profile experiments and proteome analyses of wild-type and phytochrome-deficient strains. While PaBphP has a pleiotropic effect on global gene expression, 66 % of the downregulated genes in the phytochrome mutant display a link to the Las QS system. Most of these genes seem to be indirectly regulated by LasR through BphP and the unknown response regulator BphR. A model of phytochrome function within the Las QS network is presented.
authors.affiliation: Physiology of Microorganisms, Ruhr-University Bochum, Universitaetsstr. 150, 44780 Bochum, Germany.
authors.forename: Katalin
authors.initials: K
authors.lastname: Barkovits
authors.affiliation: Physiology of Microorganisms, Ruhr-University Bochum, Universitaetsstr. 150, 44780 Bochum, Germany.
authors.forename: Britta
authors.initials: B
authors.lastname: Schubert
authors.affiliation: Physiology of Microorganisms, Ruhr-University Bochum, Universitaetsstr. 150, 44780 Bochum, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Heine
authors.affiliation: Institute for Microbiology, Technical University Braunschweig, 38106 Braunschweig, Germany.
authors.forename: Maurice
authors.initials: M
authors.lastname: Scheer
authors.affiliation: Physiology of Microorganisms, Ruhr-University Bochum, Universitaetsstr. 150, 44780 Bochum, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Frankenberg-Dinkel
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D010834:Phytochrome / Q000235:genetics / Q000378:metabolism*; D020543:Proteome; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D053038:Quorum Sensing; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C080365:LasR protein, Pseudomonas aeruginosa; D020543:Proteome; D012808:Sigma Factor; D015534:Trans-Activators; C069567:sigma factor KatF protein, Bacteria; D010834:Phytochrome