Supplemental Figure 6: Single-cell expression data at different growth rates from Division rate, cell size and proteome allocation: impact on gene expression noise and implications for the dynamics of genetic circuits

Average protein expression and noise for three promoter-GFP fusions constructs at different growth rates. Data from Nikolic et al. (2013). As growth rates for batch cultures were not reported, we used values for matching media and background strain from Thakur et al. (2010). Contribution of cell-to-cell variability in size within each condition was reduced by stringent gating. mglB and ptsG encode for components of glucose transport systems, and rpsM encodes for a ribosomal protein. Interestingly, consistently with our modeling predictions presented in Figure 4, for the mglB promoter noise decreases with growth rate despite a decrease in average expression. Average expression from ptsG and rpsM promoters increases with the growth rate, and noise also decreases, as trivially expected for R-like growth rate dependency. Note that mglB and ptsG expression behaviors differ despite encoding proteins of the same functional class, presumably because of known differences in their regulation (Nikolic et al, 2013).