title: The periplasmic protein MppA requires an additional mutated locus to repress marA expression in Escherichia coli.
abstract: Escherichia coli strain TP985, which has an insertional mutation in the gene for the periplasmic murein tripeptide binding protein MppA, was previously reported to overproduce MarA and exhibit a multiple-antibiotic resistance (Mar) phenotype (H. Li and J. T. Park, J. Bacteriol. 181:4842-4847, 1999). We found that TP985 contained a previously unrecognized marR mutation which was responsible for the Mar phenotype. Transduction of the mppA mutation from TP985 to another wild-type strain did not affect antibiotic susceptibility. Overproduction of MppA repressed marA transcription in TP985 but not in other mppA or marR mutants. Therefore, TP985 contains an additional unknown mutation(s) that facilitates the repression of marA expression by MppA.
authors.affiliation: Center for Adaptation Genetics and Drug Resistance, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Bina
authors.forename: Vincent
authors.initials: V
authors.lastname: Perreten
authors.forename: Stuart B
authors.initials: SB
authors.lastname: Levy
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D033902:Periplasmic Binding Proteins / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D000900:Anti-Bacterial Agents; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C080002:MarA protein, E coli; D026901:Membrane Transport Proteins; C110966:MppA protein, E coli; D033902:Periplasmic Binding Proteins