Figure 6. Transcription activity within the axe-txe operon.

Multi-round in vitro transcription experiments were performed using E. coli σ⁷⁰ RNA polymerase holoenzyme and pTE103 template DNA containing the whole axe-txe operon fragment (2), the same fragment but with the p _axe promoter mutated (1), or the fragment with the axe gene and first 60 base pairs of the txe gene (3). The band marked as p _txe corresponds to the transcript which derives from as yet unidentified p _txe promoter. Reactions were performed and analysed as outlined in Materials and Methods. Transcript sizes were estimated according to an RNA ladder (RiboRuler Low Range RNA Ladder – Thermo Scientific) which was electrophoresed with the reactions and then excised and stained with ethidium bromide.