Expression of the pho regulon interferes with induction of the uhpT gene in Escherichia coli K-12

Citation
Sm. Hoffer et al., Expression of the pho regulon interferes with induction of the uhpT gene in Escherichia coli K-12, ARCH MICROB, 176(5), 2001, pp. 370-376
Citations number
41
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
ARCHIVES OF MICROBIOLOGY
ISSN journal
0302-8933 → ACNP
Volume
176
Issue
5
Year of publication
2001
Pages
370 - 376
Database
ISI
SICI code
0302-8933(200111)176:5<370:EOTPRI>2.0.ZU;2-9
Abstract
The uptake of hexose 6-phosphates in Escherichia coli is mediated by the tr ansporter UhpT, the synthesis of which is induced by the presence of glucos e 6-phosphate (glucose 6-P) in the medium. Since this protein functions as an anion exchanger, it is generally assumed to be geared for the use of sug ar phosphates as a carbon source. However, the question was unresolved whet her this transporter can also provide the cells with glucose 6-P as a phosp hate source. It is demonstrated in this work that UhpT-mediated glucose 6-P uptake does not allow the cells to grow on glucose 6-P as phosphate, sourc e. Hence, the expression of UhpT under phosphate limitation would not be pa rticularly advantageous and some form of interaction between the uhp system and the Pi-limitation-inducible pho regulon, the products of which are inv olved in phosphate acquisition, may be anticipated. Indeed, the use of an u hpT-lacZ fusion revealed that much higher concentrations of the inducer glu cose 6-P were required to elevate uhpT transcription when the pho regulon w as expressed. This interference was the result of degradation of glucose 6- P by one of the products of the pho regulon, the periplasmic enzyme alkalin e phosphatase. The specific form of interaction between the Pho and Uhp sys tems is designated inducer degradation.