FIG. 3.

Schematic representation of the intergenic nrfA-acs region depicting the approximate extent and/or location of the nrfA promoter, the acs promoters P1 and P2 (A. J. Wolfe et al., unpublished data), selected restriction sites [M, MunI; S, SphI; (A), ApoI introduced by site-directed mutagenesis], primers used for RT-PCR analyses, and acs::lacZ transcription fusions used in this study. The nucleotide immediately 5′ to the ATG codon that encodes the translation initiation site of the acs open reading frame was arbitrarily chosen as ⁻1.