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Noise-induced dynamics in the mixed-feedback-loop network motif.

Difei Li¹, Chunguang Li

¹Centre for Nonlinear and Complex Systems, School of Electronic Engineering, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China.

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

|March 21, 2008

Summary

This study models the mixed-feedback loop (MFL) in cellular networks, revealing how noise enhances its function. Noise enables a gene expression switch and amplifier, and can even create oscillations for robust biological timing.

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Area of Science:

Systems Biology
Biophysics
Computational Biology

Background:

The mixed-feedback loop (MFL) is a key motif in gene regulatory and protein-interaction networks.
MFLs can function as bistable switches or oscillators, crucial for cellular decision-making.
Understanding noise effects on MFL dynamics is vital for comprehending cellular behavior.

Purpose of the Study:

To develop a stochastic model for the MFL and analyze noise impacts.
To investigate how extrinsic and intrinsic noise influence MFL dynamics, including switching and oscillation.
To explore the potential of noise for enhancing MFL performance and control.

Main Methods:

Stochastic modeling of the mixed-feedback loop (MFL).
Bifurcation analysis to identify switch and oscillator regimes.
Systematic investigation of extrinsic and intrinsic noise effects on MFL dynamics.

Main Results:

MFL exploits noise to enhance dynamic behaviors like switching and amplification.
Extrinsic noise induces rapid switching between states with significant protein production amplification.
Intrinsic noise can drive oscillations (stochastic resonance) in systems where deterministic models do not oscillate.

Conclusions:

The MFL can utilize noise as a functional component for gene expression control.
Noise-induced switching and oscillation offer robust mechanisms for cellular regulation and timing.
The MFL demonstrates potential as a controllable, noise-driven biological switch and amplifier.