Application of yeast cells transformed with GFP expression constructs containing the RAD54 or RNR2 promoter as a test for the genotoxic potential of chemical substances

Yeast strains transformed with high copy number plasmids carrying the gene encoding a green fluorescent protein optimised for yeast (yEGFP3) under the control of the RAD54 or RNR2 promoter were used to investigate the activit y of potentially DNA-damaging substances. The assays were performed on 96-w ell microtitre plates in the presence of different concentrations of the te st substances. The synthesis of GFP protein was measured through the fluore scence signal and cell growth was monitored by absorption. Here, we demonst rate that this system can be used as a biosensor to assess the genotoxic po tential of drugs and other chemical substances. The use of microtitre plate s will enable full automation of the system and allows the inclusion of int ernal reference standards in each assay. (C) 2000 Elsevier Science B.V. All rights reserved.