Promoter mapping of rhlG. A: Schematic representation of the rhlG locus. Black flags indicate the promoters PAlgU, Pσ54, and Pσ70; and arrows indicate the rhlG and PA3388 genes. B: Annotated sequence of the rhlG promoter region. Black triangles indicate the three transcription start sites (+1) and the negative numbers provide their position relative to the rhlG translation initiation codon. The promoter sequences recognized by the sigma factors AlgU, σ54, and σ70 are respectively point over lined, full trait over lined, and underlined. The “lux box” as proposed in  is boxed with the two highly conserved dinucleotides underlined. The chromatograms show the results of 5′-RACE PCR allowing us to identify the major transcription start sites resulting from PAlgU and the minor from 1 Pσ70, the white arrow corresponding to the last base before the polyC tail added to the 5′ extremity of cDNA. The transcription start site resulting from Pσ54 was identified in .