Fig. 5.
rpaA deletion has opposite effects on class 1 and class 2 promoters. Shown for comparison are the WT (filled black squares), ΔkaiC (filled black diamonds), and ΔrpaA (open red squares) for PkaiBC (A) and PpurF (B). Note that the RpaA knockouts have the opposite effect of the KaiC knockouts in both promoter classes. (C) Phospho-RpaA is present in all of the KaiC phosphomimetics. Samples were taken 9 h after lights on following a 12-h dark entrainment, and the ratio of P-RpaA to RpaA is provided. (D) Plot of bioluminescence reported by PpurF::luc in strains with (open red squares) and without (open cyan circles) the KaiC oscillator protein in an rpaA deletion background. The level measured in the strain containing the KaiC oscillator protein is approximately three- to fivefold greater than the strain lacking KaiC. This difference, which is comparable with the peak:trough ratio of the measured WT oscillations (shown B), indicates that there is a significant oscillator output that affects PpurF expression in the absence of RpaA.