Figure 2. EUO represses transcription of σ²⁸-dependent promoters.

A. Representative in vitro transcription assay for each promoter, which was present on a supercoiled transcription plasmid at a concentration of 13 nM. Transcription reactions were performed with σ²⁸ RNA polymerase in the absence or presence of 2.5 µM rEUO. σ⁶⁶-dependent control promoters were transcribed with E. coli holoenzyme. These gels do not reflect the relative strength of the promoters because different amounts of transcription reaction were used for each promoter in order to have a similar baseline transcription in the absence of EUO. However for a given promoter, the same amount of transcription reaction in the absence or presence of EUO was analyzed. B. Graph of the effect of EUO on transcriptional activity. For each promoter, transcription in the presence of EUO was normalized to baseline transcription in the absence of EUO. Values are from the average of at least three independent experiments with standard deviation indicated by the error bar.