Figure 6.

Artificial TF induction of GFP in yeast. We previously described a system to induce an artificial ZF-EV with β-estradiol (25). Activation of GFP can be induced with β-estradiol if a target complementary to the zinc finger used is placed in the promoter upstream of the GFP coding sequence. To provide a sense of relative specificity and affinity, the helices described in Figure 5, and the GAG-binding fingers described in Figure 4, were challenged with a set of similar targets, listed across the bottom of the chart. Each experiment included a positive control, the Zif268 activity when paired with its consensus target. This allows for the GFP output to be normalized in each experiment to the positive control output. Here, the normalized GFP output for each zinc finger and binding site pair is shown as a heat plot. For reference, a key is provided that shows the normalized GFP output when Zif268 is paired with binding sites of known affinity relative to the consensus (64). Asterisk: helices underlined and in italics were tested as suggested in the literature to bind the target noted on the left (67).