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Hidden hysteresis - population dynamics can obscure gene network dynamics.
Phillip Poisson1, Kaustubh D Bhalerao
1Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, 1304 W Pennsylvania Ave, Urbana, IL 61801, USA. bhalerao@illinois.edu.
Journal of Biological Engineering
|June 27, 2013
Summary
Cell population dynamics significantly impact synthetic gene circuit hysteresis. Higher cell dilution reduces observed hysteresis, highlighting the need to consider population effects in synthetic biology.
Area of Science:
- Synthetic biology
- Gene regulatory networks
- Systems biology
Background:
- Positive feedback loops are common in gene regulatory networks.
- Synthetic gene circuits utilize positive feedback for amplification and creating bistable systems with hysteresis.
- A synthetic tetracycline sensor in E. coli was used to investigate population dynamics' effect on hysteresis.
Purpose of the Study:
- To determine the influence of cell population dynamics on the hysteretic response of a synthetic gene circuit.
- To understand how factors like cell concentration and dilution affect gene circuit behavior.
Main Methods:
- Utilized a synthetic positive feedback-based tetracycline sensor in E. coli.
- Inoculated subcultures with varying cell concentrations and dilution factors.
- Monitored gene expression levels and cell growth dynamics.
Main Results:
- Hysteresis magnitude in the cell population was dependent on initial cell concentration.
- Higher dilution of cell cultures led to lower observed hysteresis.
- Individual cell circuit behavior remained consistent, but the proportion of high-expression cells varied with dilution.
Conclusions:
- Population dynamics are critical and cannot be overlooked when analyzing gene network dynamics.
- Population dynamics significantly influence the manifestation of bistability and hysteresis in synthetic gene circuits.
- Consideration of population dynamics is essential for designing robust synthetic gene circuits for long-term applications.
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