Regulation of the phosphate regulon of Escherichia coli: analysis of mutant phoB and phoR genes causing different phenotypes.
AUTOR(ES)
Yamada, M
RESUMO
The phoB gene product of Escherichia coli is the transcriptional activator for the genes in the phosphate regulon as well as for phoB itself, all of which are induced by phosphate starvation. The phoR gene product modulates PhoB function in response to the phosphate concentrations in the medium. We quantitatively compared the levels of expression of the phoA, phoB, phoE, and pstS genes in several phoB mutants with different phenotypes by constructing operon fusions of these genes with the gene for chloramphenicol acetyltransferase. Although all the phoB mutants examined had little activator function for phoA, three among the four mutants showed various levels of the activator function for phoB, pstS, and phoE. To study the functional motifs of the PhoB and PhoR proteins, we cloned and sequenced the four classical phoB and six phoR mutant genes. All of the phoB mutations and one of the phoR mutations were missense mutations, and most of the altered amino acids were in the highly conserved amino acids among the regulatory proteins homologous to PhoB or PhoR protein, such as the OmpR, SfrA, and VirG proteins or the EnvZ, CpxA, and VirA proteins. The other five phoR mutations were nonsense mutations.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=210403Documentos Relacionados
- Overproduction of acetate kinase activates the phosphate regulon in the absence of the phoR and phoM functions in Escherichia coli.
- Dual Transcriptional Regulation of the Escherichia coli Phosphate-Starvation-Inducible psiE Gene of the Phosphate Regulon by PhoB and the Cyclic AMP (cAMP)-cAMP Receptor Protein Complex
- Cross talk to the phosphate regulon of Escherichia coli by PhoM protein: PhoM is a histidine protein kinase and catalyzes phosphorylation of PhoB and PhoM-open reading frame 2.
- Nucleotide sequence of the Pseudomonas aeruginosa phoB gene, the regulatory gene for the phosphate regulon.
- A Dominant Constitutive phoR Mutation in ESCHERICHIA COLI