Automatic Control of Gene Expression in Mammalian Cells

Area of Science:

• Synthetic Biology
• Biotechnology
• Control Engineering

Background:

• Precise control of gene expression is crucial for understanding biological systems and engineering synthetic circuits.
• Maintaining optimal expression levels is key for reliable performance of synthetic gene circuits.

Purpose of the Study:

• To develop and validate a microfluidics-based method for real-time, automatic control of gene expression in mammalian cells.
• To apply negative-feedback control engineering principles to achieve stable, intermediate gene expression levels.

Main Methods:

• A microfluidics platform was utilized to deliver tetracycline or standard medium.
• Two model-independent control algorithms, relay and proportional-integral (PI), were implemented.
• Gene expression was monitored using a d2EYFP fluorescent reporter in cells with a tetracycline-inducible promoter.

Main Results:

• Both relay and PI controllers successfully regulated d2EYFP expression to 50% of maximum levels for extended periods (up to 3500 min).
• The PI controller demonstrated dampened oscillations around the set point compared to the relay controller.
• The system achieved precise, real-time control over gene expression in a monoclonal cell population.

Conclusions:

• Microfluidics combined with feedback control offers a robust method for precise gene expression regulation in mammalian cells.
• This technology enables fine-tuning of synthetic gene circuits and facilitates the study of gene regulatory networks.
• The developed controllers provide a foundation for advanced synthetic biology applications requiring dynamic gene expression control.