Figure 4. Graphical representation of the different modes of gene expression control.

This plot of lnk versus ln[mRNA] represents, for each mRNA, the modulations of these parameters between two conditions (i.e. different growth rates). The opposite slope of this plot corresponds to the degradational regulation coefficient ρ_D. Control solely by degradation is represented by the dotted line (I), control solely by transcription is associated to the x-axis (II). Slopes grouped in the hatched, dark gray and light gray areas reveal respectively shared (III), mainly degradation-related (IV) and mainly transcription-related (V) control.