Nucleotide sequence of the genes involved in phosphate transport and regulation of the phosphate regulon in Escherichia coli

Abstract

The pstA(=phoT), pstB and phoU genes are situated at 84 minutes on the Escherichia coli genetic map. All of them are involved in the negative regulation of the phosphate regulon, and all of them except for phoU are required for the binding-protein-mediated, highly specific phosphate transport. We have determined the DNA sequence of about 4 X 10(3) bases of chromosomal segment containing these genes. Four translational reading frames (TRFs) were detected in the region. We attempted to assign the TRFs to the mutant alleles. Plasmids were constructed so that each contained only one of the TRFs, downstream from the lac promoter, to be used for the complementation tests. By this test, TRF-2, TRF-3 and TRF-4 were identified with the pstA(=phoT), pstB and phoU genes, respectively. Alkaline phosphatase-constitutive mutations of the two strains in our collection were complemented by the plasmid with the TRF-1 region. Therefore, we propose to designate the allele phoW. The order of the genes in this region has been established to be phoS-phoW-pstA(=phoT)-pstB-phoU counterclockwise on the E. coli genetic map.