Figure 5
From: How reliable is the linear noise approximation of gene regulatory networks?
CV of mRNA and protein fluctuations in gene autoregulation. In (a) CVs of mRNA and protein levels are shown as function of the average repressed promoter fraction by variation of the transcription rate k0. The result obtained using the LNA indicates that the CVs of mRNA and unphosphorylated protein are minimized when the repressed promoter fraction is small (10 - 15%) which is in good agreement with stochastic simulations. In (b) we compare the mRNA CV obtained using the LNA with the IOS as function of the average occupation of repressed promoters varied through the protein-DNA association rate k3 which is a measure of feedback strength. While the LNA predicts the CV to have a maximum for moderately repressed promoters the IOS analysis shows a monotonically increasing dependence on the feedback strength with significantly smaller noise levels. The latter is confirmed by stochastic simulations.