Fig 4.

citZ locus transcript levels in the citB null mutant. (A) Overview of the citZ locus. The citrate synthase II (citZ), isocitrate dehydrogenase (icd), and malate dehydrogenase (mdh) genes are transcribed by promoters P₁, P₂, and P₃ (putative) to produce mono- and polycistronic messages. In addition, posttranscriptional processing of the full citZ-icd-mdh transcript likely contributes to the monocistronic transcript pools. Transcript lengths are indicated. (B) Northern blot analysis of citZ locus transcripts in the wild type and the citB null mutant. RNA was isolated from wild-type (168) and citB null (GP1441) strains grown in CSE minimal medium and analyzed by Northern blotting using probes specific for the citZ, icd, and mdh sense RNAs.