Fig. 3
GAL80 deletion affected the activities of synthetic promoters under different carbon sources. a The regulation mechanism of GAL1 promoter under galactose and glucose condition. Gal4p: the transcriptional activator responsible for galactose induction; Gal80p: the repressor of Gal4p; Mig1p: the repressor that responds to glucose. WT: Wildtype strain; Δgal80: GAL80 deletion strain. b, c GAL80 deletion improved the activities of GAL promoters in the presence of 2% galactose (b) or 2% glucose (c). The promoter activities were continuously monitored for 36 h. d Glucose inhibition profile of promoters. Synthetic promoters were incubated with 2% raffinose with a glucose gradient from 0 to 2% for 5 h with initial OD600 at 0.1. After inhibition, mean fluorescence intensity of cells was analyzed by flow cytometry. e Galactose induction profile of native and synthetic promoters. 2% raffinose was used as background carbon source with galactose gradient concentration from 0 to 2% for 5 h with initial OD600 at 0.1. After induction, mean fluorescence of intensity of cells was analyzed by flow cytometry. Data are mean ± SD from three biological replicates and the shadow patterns of the curve represents errors as standard deviation