Fig. 4: Creation and evolution (as assessed by S/N ratio, sensitivity, and behaviour type) of yeast transcriptional switches.
From: Robust and flexible platform for directed evolution of yeast genetic switches
a Yeast genetic switches developed in this study. The plasmid expression of the identified sTA variants provided dose-dependent activation genes placed under the control of pphlO1, pcamO1, or pluxO1 in the host cells. The transfer function of the parent and variants of the DAPG-OFF switch (b), Camphor-OFF switch (c), DAPG-ON switch (d), and HSL-ON switch (f). TBG-derived GFP fluorescence is plotted as a function of each inducer concentration. Error bars shown represent the mean ± SD of three independent experiments. The concentrations of inducers added during the OFF/ON selections are indicated by arrows and dashed lines. The EC50 values were calculated from the dose–response curves fitted to the Hill equation by the least-squares method and are expressed in micromolar concentration units. e, g Structural mapping of mutations in PhlF and LuxR that reversed/sensitized PhlTA, and sensitized LuxTA, respectively. The structures of PhlF and LuxR were modelled using the Swiss-Model server54 based on the crystal structure of the TetR family transcription regulator SCO0332 (PDB: 2ZB9) and quorum-sensor protein TraR (PDB: 1L3L), respectively. The DNA structures are taken from the corresponding reference crystal structures. Source data are available in the Source Data file.
