A conserved two-component signal transduction system controls the response to phosphate starvation in Bifidobacterium breve UCC2003.
This work reports on the identification and molecular characterization of the two-component regulatory system (2CRS) PhoRP, which controls the response to inorganic phosphate (P(i)) starvation in Bifidobacterium breve UCC2003. The response regulator PhoP was shown to bind to the promoter region of pstSCAB, specifying a predicted P(i) transporter system, as well as that of phoU, which encodes a putative P(i)-responsive regulatory protein. This interaction is assumed to cause transcriptional modulation under conditions of P(i) limitation. Our data suggest that the phoRP genes are subject to positive autoregulation and, together with pstSCAB and presumably phoU, represent the complete regulon controlled by the phoRP-encoded 2CRS in B. breve UCC2003. Determination of the minimal PhoP binding region combined with bioinformatic analysis revealed the probable recognition sequence of PhoP, designated here as the PHO box, which together with phoRP is conserved among many high-GC-content Gram-positive bacteria. The importance of the phoRP 2CRS in the response of B. breve to P(i) starvation conditions was confirmed by analysis of a B. breve phoP insertion mutant which exhibited decreased growth under phosphate-limiting conditions compared to its parent strain UCC2003.
Alimentary Pharmabiotic Centre, National University of Ireland, Cork, Ireland.
Pablo
P
Alvarez-Martin
Matilde
M
Fernández
Mary
M
O'Connell-Motherway
Kerry Joan
KJ
O'Connell
Nicolas
N
Sauvageot
Gerald F
GF
Fitzgerald
John
J
MacSharry
Aldert
A
Zomer
Douwe
D
van Sinderen
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001644:Bifidobacterium / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D001665:Binding Sites / Q000235:genetics; D019295:Computational Biology; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics / Q000502:physiology*; D046228:Microarray Analysis; D016254:Mutagenesis, Insertional / Q000235:genetics; D009841:Oligonucleotides / Q000235:genetics; D028061:Phosphate Transport Proteins / Q000235:genetics / Q000378:metabolism; D010710:Phosphates / Q000172:deficiency*; D010766:Phosphorylation; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D014170:Transformation, Genetic
D001426:Bacterial Proteins; D009841:Oligonucleotides; D028061:Phosphate Transport Proteins; D010710:Phosphates; C061064:PhoP protein, Bacteria