TY - JOUR
T1 - The relation between ppGpp and the PHO regulon in Escherichia coli
AU - Spira, B.
AU - Yagil, E.
N1 - Funding Information:
Acknowledgements We thank Jon Beckwith, Mike Cashel, Kozo Makino and Barry Wanner for sending us strains and plasmids. This work was supported by a grant from the Kurt Lion Foundation
PY - 1998
Y1 - 1998
N2 - Starving of Escherichia coli cells for inorganic orthophosphate (Pi) results in the accumulation of spoT-dependent ppGpp and induces the expression of genes of the PHO regulon. In a ΔrelA ΔspoT strain that is unable to accumulate ppGpp the expression of two genes (phoA and pstS) that belong to the PHO regulon is impaired, even in constitutive mutants. The transcription of phoA and of pstS is not affected in the ppGpp0 strain, and therefore this impairment is due to a post-transcriptional defect. Conversely, overexpression of ppGpp inhibits transcription of these two PHO regulon genes. In phoB mutants, the accumulation of ppGpp during Pi starvation is diminished, suggesting that PhoB or one of the PHO products is involved in the control of ppGpp accumulation. We propose that the presence of ppGpp in the cell, but not its accumulation as a result of the starvation stress, is important for the expression of the PHO genes.
AB - Starving of Escherichia coli cells for inorganic orthophosphate (Pi) results in the accumulation of spoT-dependent ppGpp and induces the expression of genes of the PHO regulon. In a ΔrelA ΔspoT strain that is unable to accumulate ppGpp the expression of two genes (phoA and pstS) that belong to the PHO regulon is impaired, even in constitutive mutants. The transcription of phoA and of pstS is not affected in the ppGpp0 strain, and therefore this impairment is due to a post-transcriptional defect. Conversely, overexpression of ppGpp inhibits transcription of these two PHO regulon genes. In phoB mutants, the accumulation of ppGpp during Pi starvation is diminished, suggesting that PhoB or one of the PHO products is involved in the control of ppGpp accumulation. We propose that the presence of ppGpp in the cell, but not its accumulation as a result of the starvation stress, is important for the expression of the PHO genes.
KW - Alkaline phosphatase
KW - Escherichia coli
KW - PHO-regulon
KW - ppGpp
UR - http://www.scopus.com/inward/record.url?scp=0031936775&partnerID=8YFLogxK
U2 - 10.1007/s004380050671
DO - 10.1007/s004380050671
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AN - SCOPUS:0031936775
SN - 0026-8925
VL - 257
SP - 469
EP - 477
JO - Molecular and General Genetics
JF - Molecular and General Genetics
IS - 4
ER -