FIG. 5.
Mapping the promoters. (A) Schematic representation (not to scale) of the fur locus (top) and chromosomal promoter fusions to the lacZ gene (bottom) inserted between the NMB1074 and NMB1075 loci. Hatched and filled arrows and boxes indicate all or part of the smpA and fur genes, respectively. The 218-bp intergenic region is highlighted. Open arrows indicate the lacZ gene. The position of the lacZ-PE primer is indicated with a small grey arrow. (B) Primer extension reactions with total RNA extracted from strains MC-furlacZ (lane 1) and MC-smpAlacZ (lane 2). Arrows mark the elongated primer products, Pfur1, Pfur2, and Psmp. (C) Nucleotide sequence of the smpA-fur intergenic region. Deduced initiations of RNA transcription are in boldface and marked with bent arrows. Putative promoter DNA elements are boxed and marked −10 and −35 at Pfur1, Pfur2, and Psmp. Nucleotides protected by Fur in DNase I protection assays are boxed with broken lines. Double-ended arrows indicate the core Fur box sequences. The translation start sites of the smpA and fur genes are in boldface and labeled accordingly.