Design and Characterisation of a Sensor Integrating Chemical and Temperature Inputs for Gene Expression

The modularity of transcription factors has facilitated the development of combinatorial promoters that regulate gene expression in response to chemical inducers. Nevertheless, controlling gene expression by the joint influence of a chemical inducer and an environmental variable, such as temperature, has not been as extensively studied or analyzed. We designed a two-input combinatorial sensor combining the action of a chemical inducer (Anhydrotetracycline, aTc) and temperature. The design was based on transcriptional regulation by the Ptet promoter and translational regulation by an RNA thermometer. The design functioned as an AND Gate, exhibiting a four-fold change between a completely ON state, with aTc at 37 ◦C, and a completely OFF state, without aTc at 29 ◦C. We mapped the design into a Logic-Symmetry space and found that the design functioned like an AND Gate with an asymmetry of 0.266. This work should contribute to developing a temperature-based combinatorial regulation system.