title: MecI represses synthesis from the beta-lactamase operon of Staphylococcus aureus.
abstract: Plasmid diploids were constructed in Staphylococcus aureus to study the effect of the repressor of methicillin resistance (MecI) on the synthesis of both beta-lactamase and the beta-lactamase repressor (BlaI). MecI-mediated repression of the synthesis of beta-lactamase was shown by reduction in the specific activity of nitrocefinase in bacteria containing a plasmid carrying mecI but not when containing the same plasmid deleted for mecI. Antisera prepared against purified MecI and against purified BlaI were used in Western blots which showed that MecI repressed the synthesis of BlaI in these diploids. The interactions between the mec operon and the bla operon are discussed.
authors.affiliation: University of Oxford, Microbiology Unit, Department of Biochemistry, South Parks Road, Oxford OX1 3QU, UK.
authors.forename: R A
authors.initials: RA
authors.lastname: Lewis
authors.forename: K G
authors.initials: KG
authors.lastname: Dyke
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D015153:Blotting, Western; D004269:DNA, Bacterial / Q000235:genetics; D004274:DNA, Recombinant / Q000235:genetics; D004171:Diploidy; D016106:Methicillin Resistance / Q000235:genetics*; D009876:Operon / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D013211:Staphylococcus aureus / Q000201:enzymology* / Q000235:genetics; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004274:DNA, Recombinant; C101640:MecI protein, Staphylococcus; D012097:Repressor Proteins; D001618:beta-Lactamases