Figure 5.

TOXE acts as a sequence-specific DNA binding protein and transcriptional activator in yeast. (A) Four tandem copies of a double-stranded oligonucleotide containing either the wild-type or the mutant tox-box (see Fig. 4) were fused in both orientations upstream of GAL1 without upstream activating sequences (UAS) fused to lacZ (27). TOXE driven by the constitutive yeast GPD promoter was expressed from a plasmid. (B) Resulting β-galactosidase activities of the various yeast strains. “TOXE expression” indicates whether the yeast cells contained the plasmid expressing TOXE.