Engineering Rapamycin-Induced Dimerization for Control of Gene Expression in Plants

Area of Science:

• Plant Synthetic Biology
• Molecular Biology
• Gene Regulation

Background:

• Chemical induction systems are crucial for controlling gene expression in plants for synthetic biology.
• Existing systems often suffer from high basal activity and unintended environmental activation.
• Developing precise and robust inducible systems is essential for advancing plant engineering.

Purpose of the Study:

• To develop and optimize a novel rapamycin-inducible FKBP-FRB split transcription factor system for plants.
• To achieve precise temporal, spatial, and quantitative control over gene expression.
• To overcome limitations of existing plant chemical induction systems.

Main Methods:

• Engineered a split transcription factor system using human FKBP12 and hFRB domains fused to DNA-binding and activation domains.
• Systematically optimized designs by varying DNA-binding domains, FRB repeats, and promoter architectures.
• Validated system performance through gene expression analysis under different rapamycin concentrations and application methods.

Main Results:

• Achieved an 87-fold increase in target gene expression from uninduced to induced states.
• Significantly reduced basal activity compared to constitutive promoters like 2×CaMV35S.
• Demonstrated high sensitivity to rapamycin at nanomolar concentrations with simple application methods (leaf spray, soil application).

Conclusions:

• The developed rapamycin-inducible FKBP-FRB system provides a robust and precise tool for gene regulation in plants.
• Offers improved control over gene expression compared to existing systems, enabling advanced synthetic biology applications.
• Has potential for further expansion using orthogonal ligands and engineered FKBP/FRB variants.