Disease relevance of blaR1

• The corresponding region upstream of the enterococcal blaZ from Enterococcus faecalis HH22 was sequenced and compared with the staphylococcal blaR1 sequence [1].
• blaI and blaR1 regulate beta-lactamase and PBP 2a production in methicillin-resistant Staphylococcus aureus [2].

High impact information on blaR1

• Insertion of Tn5404 close to resR and to the structural and regulatory beta-lactamase genes (blaZ, blal, blaR1) of pIP1066, generated a 3.5 kb invertible segment flanked by inversely repeated resolution sites (resR, resL) [3].
• The DNA sequence between blaR1 and a Tn4001-like element was determined [4].
• The production of PBP2' is under dual control by its own mecR1-mecI- and the penicillinase blaR1-blaI-encoded regulatory elements [5].
• A mutation in blaR1 that resulted in the complete repression of PBP 2a production altered the phenotypic expression of methicillin resistance in that strain, as evidenced by efficiency-of-plating experiments [6].
• Recent reports have revealed the presence of two adjacent genes upstream of the staphylococcal blaZ thought to be the antirepressor (blaR1) and repressor (blaI) genes [1].

Other interactions of blaR1

• The mec and bla regulators, mecR1-mecI and blaR1-blaI, respectively, encode inducer-repressors with sufficient amino acid homology to suggest that they could coregulate PBP2a production [7].
• RESULTS: All penicillin-resistant strains carried blaZ and showed a similar organization of blaR1 and blaZ [8].
• The presence of mecR1/mecI and blaR1/blaI genes correlated with the expression of low-level methicillin resistance in CNS [9].

Analytical, diagnostic and therapeutic context of blaR1

• Furthermore, the presence of blaZ and blaR1 and the location of blaZ was determined by PCR and hybridisation [10].

References