High-Throughput Screen for Identifying Small Molecules That Target Fungal Zinc Homeostasis
Figure 2
Zinc responsiveness of ZRE-GFP promoter-reporter construct.
A) Comparison of Zn-dependent GFP fluorescence in untransformed yeast cells (gray bars) and yeast transformed with the ZRE-GFP promoter-reporter construct (black bars). Cells were grown in LZM medium with indicated zinc concentrations. GFP fluorescence and cell density were measured after 20 hours of incubation at 30°C. The inset shows a power law fit through the data. The excellent quality of the fit (the linear correlation coefficient between the fluorescence and the zinc concentration to the power −0.372 is R = 0.993) indicates that the fluorescence decreases with increasing zinc concentration in a scale-free manner. B) Metal specificity of the promoter-reporter construct. Transformed cells were grown in LZM either without (black bars) or with 100 µM (gray bars) of indicated metal ions and analyzed as before. GFP fluorescence is expressed as percent of non-supplemented control. The fluorescence signal was always normalized by cell density. Error bars represent standard deviation (SD).