Light-driven synchronization of optogenetic clocks

Area of Science:

• Synthetic Biology
• Genetic Engineering
• Systems Biology

Background:

• Synthetic genetic oscillators are crucial for programming periodic gene expression in engineered cells.
• Cell-to-cell variability in these oscillators leads to population desynchronization, limiting their applications.
• Controlling the phase and synchrony of synthetic clocks at the population level remains a challenge.

Purpose of the Study:

• To develop an optically controllable synthetic genetic clock.
• To investigate methods for synchronizing and entraining populations of synthetic oscillators.
• To understand the robustness of optical control mechanisms from single-cell to population dynamics.

Main Methods:

• Construction of the optorepressilator, a synthetic repressilator network in E. coli, integrated with an optogenetic module.
• Application of optical inputs (green light pulses) to reset, delay, or advance the phase of the genetic clock.
• Experimental observation of population behavior and synchronization dynamics.
• Mathematical modeling to quantitatively analyze the entrainment mechanism and robustness.

Main Results:

• Demonstration of population synchronization via transient green light exposure.
• Entrainment of the optorepressilator population to oscillate indefinitely using pulsed light stimuli.
• Observation of multiple regimes of global synchronization in response to detuned external stimuli.
• Quantitative understanding of the entrainment mechanism across single-cell and population levels.

Conclusions:

• The optorepressilator provides a robust, optically controllable synthetic clock.
• Optical inputs can effectively synchronize and entrain populations of synthetic genetic oscillators.
• The developed system offers a powerful tool for programming cellular behavior and understanding biological clock mechanisms.