[Mutations altering the specificity of the sensor RNA encoded by the Bacillus subtilis pbuE gene].

Site-directed mutagenesis was used to study the leader region of the Bacillus subtilis pbuE gene, which codes for adenine-specific sensor RNA. Two nucleotide substitutions, 70U --> C and A100 --> G, in the conserved region (A box) of the leader changed the specificity of the sensor RNA in vivo: guanine acted as a positive transcription effector in place of adenine.