Figure 2.

The promoter region of lhrC5 contains a LisR-responsive element. (A) Alignment of the five lhrC promoters. The promoter sequences were aligned using ClustalW 2.0 (47). Conserved nucleotides are marked in gray. Conserved nucleotides substituted in mutant derivatives of the lhrC5 promoter are shown in red. Numbers refer to lhrC5; +1 corresponds to the transcriptional start site. (B) Transcriptional reporter gene fusions of truncated lhrC5 promoter. Promoter regions from −70, −55, −38 and −28 to + 87 relative to the lhrC5 transcriptional start site were fused to a promoter-less lacZ gene in pTCV-lac. The complete intergenic region between the upstream gene (lmo0946) and lhrC5 was used as a positive control (wt). Samples for β-gal assays were taken from cultures stressed with cefuroxime for 1 h and from corresponding control samples. The presented β-gal activities are the average of three independent experiments each conducted in duplicates. (C) Transcriptional reporter gene fusions of lhrC5 promoter mutants. The lhrC5 promoter was substituted at indicated positions and such mutated promoters tested as described in (B).