Designer gene networks: Towards fundamental cellular control.

Area of Science:

• Synthetic biology
• Genetic engineering
• Systems biology

Background:

• Engineered control of cellular function via synthetic genetic networks is emerging.
• Naturally occurring networks serve as blueprints for artificial designs.
• Model formulation is key for computational and analytical approaches in nonlinear dynamics and statistical physics.

Purpose of the Study:

• To review synthetic gene networks, focusing on genetic switches and oscillators.
• To derive a deterministic model for single-gene networks and analyze bistability and hysteresis.
• To demonstrate the utility of model analysis in designing synthetic gene regulatory networks.

Main Methods:

• Derivation of a deterministic model for protein concentration in single-gene networks.
• Formulation of external noise effects on protein degradation rates.
• Construction of synthetic networks including switches, relaxation oscillators, and toggle switches.

Main Results:

• Bistability and hysteresis observed in protein concentration due to autoregulatory feedback.
• External noise pulses used to switch protein concentration.
• Relaxation oscillators constructed, with frequency dependence on tunable parameters.
• Resonance induces oscillations and signal amplification in synthetic networks.
• Comparison of switching properties between positive and negative regulatory element networks.

Conclusions:

• Model analysis is crucial for designing synthetic gene regulatory networks.
• Synthetic networks can be engineered for precise cellular control, including switching and oscillation.
• The study highlights design criteria for robust oscillations and signal amplification.