Figure 2From: Threshold-dominated regulation hides genetic variation in gene expression networksGraphical solution of the equilibrium condition of Eq. (2) for varying steepness of the response function and varying relative degradation rates. The blue curves are graphs of r + α(1 - Z), the straight lines graph the degradation term γ y. For intermediate values of γ the equilibrium concentration is close to θ and approaches θ when the response function steepness increases (red line), and there is active regulation. When γ is small, the basal transcription rate is sufficient to balance the degradation, and y* gets large (green line). When γ is large, degradation is so rapid that the protein concentration never reaches the level where it regulates. Maximal production is necessary to balance the degradation (magenta line).Back to article page