Figure 3.

Characterization of the Composite Promoters

(A) Experimental layout. Both the ectopic mammalian TF and the amplifier activator are induced with Dox. Different combinations of transcriptional inputs are achieved by withholding either the TF- or the amplifier activator-expressing cassette.

(B) Schematics of different transcriptionally active complexes. DBD, DNA binding domain; AD, activation domain.

(C) Expression levels reached with either or both transcriptional inputs provided to the promoter, as indicated. Different REs are compared.

(D) Effect on synergy of swapping the DBD of the amplifier activator from PIT to ET for three REs of HNF4A.

(E) Effect on synergy of replacing the TF input and its RE without changing the amplifier activator ET-VP16.

(F) Effect on synergy of swapping the minimal promoter from the minimal TATA box to CMV_MIN.

(G) Comparison between feedback-amplified sensors harboring a minimal TATA box (top) and those harboring CMV_MIN (bottom) with and without the TF input. 1×, 2×, and 3× HNF1A/B REs are compared.

In all panels, each bar represents mean ± SD of biological triplicates.