FIG. 2.
sodA transcription. (A) sodA coding for MnSOD was interrupted with Ω DNA (Kmr) to generate mutant SA1. A 0.7-kb sodA transcript is indicated by an arrow below the restriction map. (B) Northern blot hybridization analysis with [α32P]CTP-labeled RNA probes corresponding to a 520-bp NsiI-SalI DNA fragment specific to sodA. RNA was prepared from the wild type and SA1. L and ES denote the growth phases, as described in the Fig. 1 legend. (C) Mapping of 5′ end of sodA transcript by primer extension. Extension with RNA from the wild type at ES growth phase is shown in lane PE. The same 32P-labeled oligonucleotide was used to generate the sequence ladder (lanes G, T, A, and C). DNA sequence is illustrated on the left, with the 5′ end of the transcript marked with an asterisk. The sodA regulatory DNA between the CpxA stop and MnSOD initiation codons is shown on the right. The −35 and −10 sequences typical of σ70-type promoter (5′ end [T] of the transcript: +1) are boxed, and a putative binding site of the ferric uptake regulator (Fur) is underlined. A putative ribosome-binding site (S-D) is also shown.