Figure 2.

Overview of our experimental system. (A) Illustration of the master strain into which we integrated all RP promoters. At a fixed chromosomal location, the master strain contains a gene that encodes for a red fluorescent protein (mCherry), followed by the promoter for TEF2, and a gene that encodes for a yellow fluorescent protein (YFP). Every RP promoter is integrated into this strain, together with a selection marker, between the TEF2 promoter and the YFP gene. (B) Strains with different RP promoters have highly similar growth rates. Shown is the growth of 71 different RP promoter strains, measured as optical density (OD). Measurements were obtained from a single 96-well plate, with glucose-rich media and a small number of cells from each strain inserted into each well at time zero. The exponential growth phase is indicated (vertical dashed gray lines). (C) Same as in B, but where the measurements correspond to mCherry intensity. Note the small variability in the intensity of mCherry, which is driven by the same control promoter across the different strains. (D) Same as in C, but where the measurements correspond to YFP intensity. Note the large variability in the intensity of YFP, which is driven by a different RP promoter in each strain. (E) Same as in C, but where the mCherry production rate of each strain is shown, measured as the difference between the mCherry levels of different timepoints, divided by the integral of the OD during the same time period (see Methods). (F) Same as in E, but where the YFP production rate of each strain is shown.