Figure 5.

Organization and expression of bla genes. (A) Gene organization. Boxed arrows stand for length/direction of indicated genes. Broken-line arrows represent transcription starts for indicated bla genes. (B) Primer extension. Primer extension assay of the RNA transcript of each bla gene was performed for strain 628 cultured with addition of increasing amounts of imipenem or ampicillin. Lanes C, T, A, and G represent Sanger sequencing reactions. Lanes 0, 3, and 6 stand for 0, 3, and 6 mg/L imipenem. Lanes 0, 200, and 400 stand for 0, 200, and 400 mg/L ampicillin. Transcription start of each bla gene is indicated by arrow with nucleotide, and minus number under arrow indicates nucleotide position upstream of indicated bla gene. Representative data from at least two independent biological replicates are shown.