FIG. 1.
Nrg1 and Sfl1 act on UAS1 and UAS2, respectively. (A) DNA fragments carrying the STA1 promoter were inserted into pLG 670-Z containing a CYC1TATA-lacZ reporter gene, yielding the pLG-UAS series. These vectors were transformed separately into KHS 182. Three independent colonies obtained with each plasmid were tested for β-galactosidase activity under repressed (2% glucose) (R) or derepressed (2% glycerol-ethanol) (D) conditions. (B) Wild-type (WT) and mutant strains were grown in synthetic medium containing 2% glucose as a carbon source. Glucoamylase activities are averages from three independent experiments. (C) Total RNA was prepared from the same strains for Northern blot analysis. The yeast actin gene (ACT1) was used as an internal control. (D) pLG-UAS1 or pLG-UAS2 was introduced into wild-type, nrg1Δ, sfl1Δ, or nrg1Δ sfl1Δ cells, and three independent transformants were tested for β-galactosidase activity under repressed conditions (2% glucose).