Fig. 7: Engineering small molecule-responsive TFs.

a The cartoon illustrates chemically responsive control of gene expression using rapamycin-inducible ZFa (RaZFa). b The effects of promoter architecture and AD on RaZFa performance were evaluated. For all RaZFa on both promoters, reporter expression was significantly higher with rapamycin than DMSO (one-tailed Welch’s t-test, all p < 0.05). Fold induction is shown above the rapamycin case for relevant conditions. c Gene expression in the absence of rapamycin was affected by VP16-FRB dose (two-factor ANOVA p < 0.001) and FKBP-ZF dose (p < 0.001), with no interaction between these variables (p = 0.14). Reporter expression after rapamycin addition was affected by VP16-FRB dose (two-factor ANOVA p < 0.001) and FKBP-ZF dose (p < 0.001) with a significant interaction between these variables (p < 0.001). d Effects of subcellular localization tags: N = nuclear, x = no localization, C = cytoplasmic. For VP64-based RaZFa, gene expression in the absence of rapamycin was affected by AD-FRB localization (two-factor ANOVA p = 0.01) and FKBP-ZF localization (p < 0.001), with no interaction between these variables (p = 0.39). For VP64-based RaZFa, gene expression after rapamycin addition was not affected by AD-FRB localization (two-factor ANOVA p = 0.26) but was affected by FKBP-ZF localization (p = 0.02), with an interaction (p = 0.001). For VPR-based RaZFa, gene expression in the absence of rapamycin was affected by AD-FRB localization (two-factor ANOVA p < 0.001) and FKBP-ZF localization (p < 0.001), with an interaction (p = 0.03). For VPR-based RaZFa, gene expression in the presence of rapamycin was affected by AD-FRB localization (two-factor ANOVA p < 0.001) but not by FKBP-ZF localization (p = 0.29), with no interaction (p > 0.05). Experiments in (c, d) use a ZF1x6-C promoter. Experiments were conducted in biologic triplicate, and data were analyzed as described in Methods. Error bars represent the S.E.M. Source data are provided in the Source Data file.