A Versatile Transcription Factor Biosensor System Responsive to Multiple Aromatic and Indole Inducers

Area of Science:

• Synthetic biology
• Microbial engineering
• Biosensor development

Background:

• Allosteric transcription factor (aTF) biosensors are crucial for microbial engineering applications.
• A limited aTF toolbox hinders the development of diverse and functional biosensors.
• Bioprospecting and ligand-specificity engineering are key to expanding aTF utility.

Purpose of the Study:

• To engineer novel salicylate biosensors using an existing aTF.
• To assess the ligand specificity of the engineered biosensor system.
• To explore the potential of the aTF for broader chemical detection.

Main Methods:

• Utilized the TetR-family repressor CmeR from Campylobacter jejuni.
• Constructed aTF genetic circuits in Escherichia coli and Saccharomyces cerevisiae.
• Evaluated promoter responsiveness to various aromatic and indole compounds.

Main Results:

• Successfully created functional salicylate biosensors in E. coli and S. cerevisiae.
• Demonstrated that CmeR-regulated promoters respond to salicylate and other aromatic/indole inducers.
• Observed relaxed ligand specificity for the CmeR-based system.

Conclusions:

• The CmeR aTF serves as a versatile tool for constructing salicylate biosensors.
• Its relaxed ligand specificity enables detection of diverse molecules in metabolic engineering.
• CmeR is a promising target for directed evolution to engineer novel chemical sensors.