Fig. 4

Protease–protease systems. a, c, e Schematics of the three-stage signaling cascades. EGFP translation is repressed by MS2-CS-cNOT7 (Stage 1), while RBP activity is disrupted by a protease (Stage 2), which is itself engineered to include a cleavage site for an orthogonal protease. When Stage 2 protease activity is inhibited by an upstream protease (Stage 3), MS2-CS-cNOT7 is able to repress target mRNAs. b, d, f Corresponding flow cytometry data for the geometric mean and standard deviation of EGFP normalized by transfection marker mKate and rescaled to no repression values. ru relative units. Significant changes determined by unpaired t-test are indicated with asterisks ***p-value < 0.001, **p-value < 0.005 n = 3 replicates. Data collected 48 h post transfection