Increased Stability of bmr3 mRNA Results in a Multidrug-Resistant Phenotype in Bacillus subtilis

A spontaneous mutant isolated in the presence of a high concentration of puromycin acquired a multidrug-resistant phenotype. Expression of the bmr3 gene was dramatically increased. A base substitution, T to A at the +4 position, detected in the mutant resulted in the stabilization of bmr3 mRNA.