A novel design of transcriptional factor-mediated dynamic control of DNA recombination.

Genetic regulation is achieved by monitoring multiple levels of gene expression, from transcription to protein interaction. Unlike common temporary transcriptional regulation methods such as the use of inducible promoters, integrases permanently edit DNA sequences. Integrases, however, require especially strict regulation when implemented in synthetic genetic systems because of the irreversible result. Here we propose to improve the regulation of site-specific integrase-based genetic system by dynamically hiding one of the attB/P sites that are essential for recombination with transcriptional factors. After effectively suppressing excessive recombination, we also validated the necessity of each of the essential components in our transcriptional factor-controlled recombination (TFCR) system. The system applied transcriptional-level regulators directly on controlling the activity of existing non-transcriptional-level trans-factor proteins by inhibiting its binding to the cis-regulatory elements. We anticipate my results to provide greater robustness for integrase components to enable safer use in systems as well as be a starting point for future cross-expression level gene regulations.