Figure 5
Massive overexpression of phospho-relay components leads to growth defects. A Haploid GEV strains carrying a high-copy plasmid with an inducible HOG pathway gene were grown in different concentrations of β-estradiol. The OD 600 after 36 hours of growth is plotted as a function of β-estradiol concentration. Each point represents the mean and standard deviation of four replicates. Overexpression of Sln1 and Ssk1 (but not Ypd1) caused a growth defect. B The same strains were grown over a finer titration of β-estradiol concentrations. The OD 600 after 36 hours is plotted. At this resolution, it is clear that the growth defect from Ssk1 overexpression is more severe than the growth defect from Sln1 overexpression at low β-estradiol concentrations. C The same strains were frogged onto plates containing different concentrations of β-estradiol. Massive overexpression of Sln1 and Ssk1 again caused a growth defect comparable to that from overexpression of Pbs2. In all experiments, the parent strain carrying the empty vector plasmid [2 μ P G A L1 scURA3] was used as a negative control.