Figure 5.
ppGpp synthesis and the expression of alternative ribosomal protein genes.(a) Different growth-phase dependent expression of genes encoding the alternative ribosomal proteins SCO0569 and SCO0570 compared to the 50S ribosomal protein genes. In each panel, the x-axis represents culture age, and the y-axis is normalized transcript abundance in log10 scale. (b) qRT-PCR shows transcription of SCO0570 is activated following induction of ppGpp synthesis. In each biological replicate experiment, R1-R3, using strain M653 [ΔrelA tipAp::relA(1.46 kb)] or the control strain M667 [ΔrelA tipAp], lane 1 corresponds to the pre-induction sample (0 minutes), and lanes 2 and 3 correspond to the samples taken 60 minutes after induction or non-induction with thiostrepton, respectively. The average of three qRT-PCR determinations is shown, and standard deviations are marked with error bars.