FIG. 1.

One- and two-input gene expression noise generation by modulating transcription and translation. (a) Illustration of the 2-state model of a slow switching gene promoter between the “on” state (with active transcription) and the “off” state (without transcription). The effect of changing the mRNA burst size “B” (No. of mRNA produced per “on” state cycle), the protein burst size “b” (No. of proteins produced per mRNA lifetime), and/or the burst frequency “F” (rate of promoter initiation into the “on” state) of the cell population. (b) Stochastic simulations for the gene circuit in panel (a) using the Gillespie algorithm⁵³ and parameters (supplementary material and Ref. 23). Distributions of cells according to their protein abundance under different conditions and changes in B, b, and/or F are plotted. (c) Change in the noise magnitude (measured by the coefficient of variation squared, CV²) versus mean protein abundance (⟨P⟩) and fold change in variance versus mean protein abundance, under the same labeled conditions across each row in (b).