Growth of yeast cells expressing CCC1 with regulatable promoters. (A) Expression of CCC1, but not NtΔCCC1, with GAL1 promoter is toxic. BY4741 (WT) cells transformed with p416TEF (vector), and ccc1Δ cells transformed with p416TEF (vector), p416GAL-CCC1 (PGAL1-CCC1), and p416GAL-NtΔCCC1 were cultivated overnight in SC-Ura and then spotted on normal SC-Ura (SC-Ura Glucose) and SC-Ura without glucose but with 2% galactose (SC-Ura Galactose). (B) Expression of CCC1 with MET17 promoter rescues toxicity. BY4743 (WT) cells were transformed with p416TEF (vector), and ccc1Δ cells were transformed with p416TEF (vector), pUG36-CCC1 (PMET17-GFP-CCC1), and pUG36-NtΔCCC1 (PMET17-GFP-NtΔCCC1). Cells were cultivated overnight in SC-Ura (which contains methionine) to inhibit CCC1 expression, and then spotted on SC-Ura-Met media with different concentrations of FAS (Fe). Plates were incubated at 30 °C and photographed.