Fig. 3: Fluoride-sensitive yeast strains enable use of FEX as a selection marker.
From: Engineered fluoride sensitivity enables biocontainment and selection of genetically-modified yeasts
a While growth of the FEX knockout (KO) strain is inhibited by μM concentrations of fluoride, transformation with a FEX-based vector restores fluoride resistance to wildtype levels. b Diagrams of centromeric (pCFEX1), episomal (pEFEX1), and integrating (pIFEX) vectors. c FACS analysis of A2aR-GFP expression from pCFEX1 and pEFEX1 reveals that a significant portion of cells exhibit background fluorescence intensities. In contrast, expression from the integrating pIFEX backbone yields a unimodal fluorescence distribution where 97% of the population displays fluorescence above background. d, e Replacement of the promoter driving FEX1 expression significantly influences A2aR-GFP yield and phenotypic homogeneity in pEFEX but has less pronounced effects on pCFEX. In c and d, histograms correspond to representative samples. Data present in a represents a single replicate for each strain. Data presented in e represents the mean of three biological replicates, and error bars represent their standard deviation. Source data are provided as a Source Data file.
