Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1998-3-24
pubmed:abstractText
Escherichia coli genes regulated by environmental inorganic phosphate (Pi) levels form the phosphate (Pho) regulon. This regulation requires seven proteins, whose synthesis is under autogenous control, including response regulator PhoB, its partner, histidine sensor kinase PhoR, all four components of the Pi-specific transport (Pst) system (PstA, PstB, PstC, and PstS), and a protein of unknown function called PhoU. Here we examined the effects of uncoupling PhoB synthesis and PhoR synthesis from their normal controls by placing each under the tight control of the arabinose-regulated P(araB) promoter or the rhamnose-regulated P(rhaB) promoter. To do this, we made allele replacement plasmids that may be generally useful for construction of P(araB) or P(rhaB) fusions and for recombination of them onto the E. coli chromosome at the araCBAD or rhaRSBAD locus, respectively. Using strains carrying such single-copy fusions, we showed that a P(rhaB) fusion is more tightly regulated than a P(araB) fusion in that a P(rhaB)-phoR+ fusion but not a P(araB)-phoR+ fusion shows a null phenotype in the absence of its specific inducer. Yet in the absence of induction, both P(araB)-phoB+ and P(rhaB)-phoB+ fusions exhibit a null phenotype. These data indicate that less PhoR than PhoB is required for transcriptional activation of the Pho regulon, which is consistent with their respective modes of action. We also used these fusions to study PhoU. Previously, we had constructed strains with precise delta phoU mutations. However, we unexpectedly found that such delta phoU mutants have a severe growth defect (P. M. Steed and B. L. Wanner, J. Bacteriol. 175:6797-6809, 1993). They also readily give rise to compensatory mutants with lesions in phoB, phoR, or a pst gene, making their study particularly difficult. Here we found that, by using P(araB)-phoB+, P(rhaB)-phoB+, or P(rhaB)-phoR+ fusions, we were able to overcome the extremely deleterious growth defect of a Pst+ delta phoU mutant. The growth defect is apparently a consequence of high-level Pst synthesis resulting from autogenous control of PhoB and PhoR synthesis in the absence of PhoU.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-1331806, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-1447208, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-1459954, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-1551836, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-166384, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-2155195, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-2182324, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-2824439, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-3011607, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-3042755, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-6304324, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-6313614, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-7559459, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-7608087, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-7789817, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-8226621, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-8230210, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-8388873, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-8664263, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-8693022, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-8962056, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-9223333, http://linkedlifedata.com/resource/pubmed/commentcorrection/9495769-9294451
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9193
pubmed:author
pubmed:issnType
Print
pubmed:volume
180
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1277-86
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Use of new methods for construction of tightly regulated arabinose and rhamnose promoter fusions in studies of the Escherichia coli phosphate regulon.
pubmed:affiliation
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.