blaI and blaR1 regulate beta-lactamase and PBP 2a production in methicillin-resistant Staphylococcus aureus.
For Staphylococcus aureus, it is hypothesized that two genes located upstream of the beta-lactamase gene, blaZ, are required for the inducible expression of beta-lactamase. blaR1 is predicted to encode a signal-transducing membrane protein, and blaI is predicted to encode a repressor protein. These same two genes may also regulate the production of penicillin-binding protein 2a (PBP 2a), a protein essential for expression of methicillin resistance. To confirm that these two genes encode products that can control both beta-lactamase and PBP 2a production, blaI, blaR1, and blaZ with a 150-nucleotide deletion at the 3' end were subcloned from a 30-kb staphylococcal beta-lactamase plasmid and three beta-lactamase-negative strains of methicillin-resistant S. aureus were transformed with the recombinant plasmid containing that insert. The production of PBP 2a and a nonfunctional beta-lactamase was detected by fluorography and by immunoblots with polyclonal antisera directed against each of the proteins. Whereas the parent strains did not produce beta-lactamase and constitutively produced PBP 2a, PBP 2a and a truncated beta-lactamase were now inducible in the transformants. Therefore, two plasmid-derived genes regulate the production of both PBP 2a and beta-lactamase.
Hackbarth
C J
CJ
University of California, San Francisco 94143.
Chambers
H F
HF
D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D001483:Base Sequence; D015139:Blotting, Southern; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D003001:Cloning, Molecular; D004790:Enzyme Induction; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D006602:Hexosyltransferases; D007106:Immune Sera; D008666:Metalloendopeptidases / Q000096:biosynthesis* / Q000235:genetics; D016106:Methicillin Resistance; D008969:Molecular Sequence Data; D002267:Muramoylpentapeptide Carboxypeptidase / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D009693:Nucleic Acid Hybridization; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D010957:Plasmids; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics; D014169:Transformation, Bacterial; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology
D001426:Bacterial Proteins; D002352:Carrier Proteins; D007106:Immune Sera; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; C569108:BlaR1 protein, Staphylococcus aureus; D008666:Metalloendopeptidases; D001618:beta-Lactamases