Effect of transcription factor resource sharing on gene expression noise
Fig 3
Our model of TF sharing predicts the behavior of the first two moments of steady-state mRNA distribution across an isogenic population.
(A) Fold change of the mRNA distribution (defined by 〈m〉/(NPr/γ)) as a function of activator number. (B) Variance of mRNA distribution (var(m)) versus activator number. Note that the variance peaks when the activator number equals the promoter number. (C) Fano factor (defined by var(m)/〈m〉) also exhibit a peak as a function of activator number, when the activator number equals the promoter number. (D) Fold change of expression as a function of repressor number. (E) Variance of mRNA distribution versus repressor number. Just like activators, the variance peaks when repressor number equals the promoter number. (F) Fano factor versus repressor number, showing peaks when the repressor number becomes comparable, but slightly higher than the promoter number. In all the plots, symbols represent data from numerical simulations, which are connected by smooth dashed lines to guide the eyes. The parameter values are as specified in Table 1.