Fig. 4: Tuning response of a layered circuit using multi-layer DNA sponges to decoy regulators within both the input sensing and signal processing modules.
From: Synthetic protein-binding DNA sponge as a tool to tune gene expression and mitigate protein toxicity
a Schematic of using dual-layer DNA sponges to tune the response of a layered circuit consisting of an AHL-responsive input sensor connected with a downstream TetR-based inverter. Sponges containing 1–80 repeats of the LuxR binding site (LBS) and 1–320 repeats of the TetR operator (tetO) are combined to decoy LuxR and TetR within the input sensing and signal processing modules respectively. b Output gene expression and induction fold of the AHL-responsive circuit with regulation by the LBS-tetO dual-layer sponges. Output gene expression (top panel) is obtained when there is no AHL induction, indicating leaky expression of TetR repressor (the higher the output, the lower the TetR leakage). Induction fold (bottom panel) is calculated using the output fluorescence intensity of the none-induced samples (top graph) divided by the fluorescence intensity of samples induced by 1.6 μM 3OC6HSL (Supplementary Fig. 11a). c Dose-responses of the two-layered AHL-responsive circuit with regulation by four different LBS-tetO sponges selected from (b). d Induction fold between uninduced and samples induced by 1.6 μM 3OC6HSL of the circuit characterized in (c). e Hill constant (KM) and maximum output (k) of the circuit’s dose-responses characterized in (c). KM value of sample (−/−) is not shown due to insufficient dose-response of the circuit. For (b), values are mean (n = 3 biologically independent samples). For (c, d), values are mean ± s.d. (n = 3 biologically independent samples). For (e), values are mean ± s.e.m. (n = 3 biologically independent samples). Fluo., fluorescence. a.u., arbitrary units. Source data are provided as a Source Data file.
