Phenotypic revertant mutations of a new OmpR2 mutant (V203Q) of Escherichia coli lie in the envZ gene, which encodes the OmpR kinase.
AUTOR(ES)
Harlocker, S L
RESUMO
The Escherichia coli ompR2 allele ompR472 contains a valine-to-methionine point mutation at position 203, resulting in an OmpF-constitutive OmpC- outer membrane phenotype. In the present study, OmpR residue V-203 was replaced with glutamine (V203Q mutation), resulting in the same outer membrane phenotype. However, unlike the OmpFc OmpC- phenotype conferred by the OmpR(V203M) mutant protein, the OmpFc OmpC- phenotype produced by the OmpR(V203Q) mutation was suppressed by the envZ11(T247R) allele. Additional suppressors of OmpR(V203Q) were isolated by random mutagenesis. All suppressor mutations were found in the envZ gene and conferred an OmpC+ OmpF- phenotype in the presence of the wild-type ompR. These envZ11-like mutations mapped to a region different from those previously reported and were incapable of suppressing the ompR(V203M) allele. Our results indicate that while methionine or glutamine replacements could cause similar effects on OmpF and OmpC expression, they conferred different abilities on the mutant proteins to be suppressed by envZ.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=204274Documentos Relacionados
- Molecular analysis of the signaling pathway between EnvZ and OmpR in Escherichia coli.
- The critical role of DNA in the equilibrium between OmpR and phosphorylated OmpR mediated by EnvZ in Escherichia coli
- EnvZ functions through OmpR to control porin gene expression in Escherichia coli K-12.
- Suppression of a mutation in OmpR at the putative phosphorylation center by a mutant EnvZ protein in Escherichia coli.
- Phosphorylation of OmpR by the osmosensor EnvZ modulates expression of the ompF and ompC genes in Escherichia coli.