Transcription activity within the <i>axe-txe</i> operon.

<p>Multi-round <i>in vitro</i> transcription experiments were performed using <i>E. coli</i> σ⁷⁰ RNA polymerase holoenzyme and pTE103 template DNA containing the whole <i>axe-txe</i> operon fragment (2), the same fragment but with the <i>p</i>_<i>axe</i> promoter mutated (1), or the fragment with the <i>axe</i> gene and first 60 base pairs of the <i>txe</i> gene (3). The band marked as <i>p</i>_<i>txe</i> corresponds to the transcript which derives from as yet unidentified <i>p</i>_<i>txe</i> 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.