Digitizing the Blue Light-Activated T7 RNA Polymerase System with a tet-Controlled Riboregulator.

Area of Science:

• Synthetic Biology
• Optogenetics
• Molecular Engineering

Background:

• Optogenetic systems provide precise gene expression control but suffer from limited dynamic range due to dark activity.
• Existing systems require improvements for broader applicability in biotechnology.

Purpose of the Study:

• To enhance optogenetic systems by improving their dynamic range and reducing leaky expression.
• To engineer a novel light-controlled gene expression system with digitized output.

Main Methods:

• Developed a split T7 RNA polymerase system fused to blue-light-inducible Magnets.
• Incorporated a tetracycline-controlled riboregulatory module sensitive to anhydrotetracycline and synthetic small RNAs.
• Implemented a repressive mechanism on polymerase fragment translation, relieved by blue light.

Main Results:

• Achieved a 13-fold improvement in dynamic range upon blue light exposure.
• Further enhanced dynamic range to 23-fold in cells pre-adapted to chemical induction.
• Demonstrated functional application through light-controlled antibiotic resistance in bacteria.

Conclusions:

• The engineered riboregulatory module effectively digitizes light-controlled gene expression.
• Integration of regulatory layers offers a robust strategy for developing improved optogenetic circuits.
• This approach advances light-based biotechnological applications requiring precise gene regulation.