Regulation of the phosphate regulon of Escherichia coli K-12: Regulation and role of the regulatory gene phoR

Add time:08/14/2019    Source:sciencedirect.com

The phoR gene product functions as a negative regulator with excess of phosphate and as a positive regulator with limited phosphate for the phosphate-starvation-inducible pho regulon of Escherichia coli. We constructed recombinant plasmids that contain a phoR′-′lacZ fusion gene to study the regulation of phoR expression. The genetic and physiological regulation of phoR expression was found to be very similar to that of phoB, a positive regulatory gene for the pho regulon, and phoA, the structural gene for alkaline phosphatase, both of which are inducible by phosphate limitation. The synthesis of the PhoR protein became non-inducible when the phoB promoter upstream of phoR, was removed from the hybrid plasmid, or when a transcriptional terminator was inserted in the phoB structural gene, irrespective of phosphate concentration in the medium. The results suggest that phoB and phoR constitute a single operon whose promoter is located proximal to phoB. The same low level of the PhoR protein in the cell can function as a positive regulator with limited phosphate and as a negative regulator with excess phosphate for the phoB-phoR operon. These results suggest that the maximal level of the operon is induced as consequences of both the increase in the quantity of the PhoR protein and of functional change of the protein as a positive regulator, which are induced by phosphate limitation.

We also recommend Trading Suppliers and Manufacturers of phoR protein (cas 107121-16-4). Pls Click Website Link as below: cas 107121-16-4 suppliers

Prev:Signal transduction in the phosphate regulon of Escherichia coli involves phosphotransfer between PhoR and PhoB proteins
Next:The two-component phoR-phoP system of Streptomyces natalensis: Inactivation or deletion of phoP reduces the negative phosphate regulation of pimaricin biosynthesis)