Fluorescence induction in yeast cells transformed with different gene constructs in response to DNA damage.

Yeast-based biosensors were either nontreated (NT, control) or exposed to increasing concentrations of AFB1 (A), BaP (B), NDMA (C), and MMS (positive genotoxin, D). CYP3A4 + RAD54: strain transformed with both CPR-CYP3A4 and RAD54-GFP constructs; RAD54: strain transformed with only the RAD54-GFP construct; NCs (negative control) system: strain transformed with two control pESC-URA and pUMGP5 plasmids. The GFP fluorescence intensity of measurements was compared within linear range of GFP signals by calculation of GFP fold induction. The horizontal dashed line at 1.3 fold GFP induction is used as cutoff or genotoxicity threshold. Other negative (untransformed yeast cells) and process (medium) controls are not presented here.