Figure 9

Sequence of expression switches associated with the metabolic switch. The expression profile of the ten most variable transcriptional regulators on the array is shown. As discussed in the main text, some of these regulators show an expression profile that clearly parallels that of the major expression clusters. These regulators are the main candidate drivers of the successive waves of gene expression that characterize the metabolic switch according to our study. They include phosphate transport system regulators (phoP, dark grey, phoU, light green, and phoR, dark green), the transcriptional regulator of the red cluster, redD (red), the pyrimidine regulatory protein pyrR (blue), as well as the nitrogen regulators glnR (light purple) and glnK (dark purple) [10]. A list of the genes and their expression data is included in Additional File 2.