Figure 3. Transcription rate.

(A) Normalized transcription rate (Equation 12) for a σ ⁷⁰-dependent promoter as a function of the number of alternative sigma factors. The numbers of and cores are fixed. The blue line is for a saturated promoter (with M) and the cyan line for an unsaturated promoter (with M). (B) Comparison of model predictions (lines) with an in vitro competition experiment [29] with a fixed amount of core and σ^H and different amounts of (stars). The plot shows the transcription rate of a σ^H-dependent gene (normalized to the maximal value) as a function of the concentration . (C) The sigma-core and the holoenzyme-promoter dissociation constants (see Table 2) are determined by fitting the results of transcription rate experiments with a fixed amount of cores in the same conditions as in (B) without competition in the presence of a DNA template containing σ^H- and σ ⁷⁰-driven genes [29], [32]. (D) When a σ ⁷⁰-dependent promoter also binds another type of holoenzyme or overlaps to another promoter, also acts as a repressor of the σ ⁷⁰-dependent transcription. (E) Normalized transcription rate of a saturated and unsaturated σ ⁷⁰-dependent promoter as a function of the number of (blue and cyan solid lines with M and M, respectively). The dashed line show the corresponding results in the absence of repression by promoter sharing or overlapping.