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An Ecdysone Receptor-based Singular Gene Switch for Deliberate Expression of Transgene with Robustness, Reversibility, and Negligible Leakiness
Published on: May 7, 2018
A bistable hysteretic switch in an activator-repressor regulated restriction-modification system.
Kristen Williams1, Michael A Savageau, Robert M Blumenthal
1Department of Medical Microbiology & Immunology, and Program in Bioinformatics, University of Toledo, Toledo, OH 43614, USA.
Nucleic Acids Research
|May 1, 2013
Summary
This study reveals how gene copy number and protein accumulation control bacterial restriction-modification systems. Experimental results confirm mathematical models, explaining the widespread nature of these essential defense mechanisms.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Restriction-modification (RM) systems are crucial bacterial defense mechanisms, often encoded by mobile genetic elements.
- Type II RM systems involve separate restriction endonuclease (REase) and DNA methyltransferase (MTase) proteins.
- Regulation of REase expression relative to MTase is vital for RM system function in new host cells.
Purpose of the Study:
- To investigate the regulatory mechanisms of the PvuII restriction-modification system.
- To experimentally validate predictions from mathematical modeling regarding gene copy number and hysteretic responses.
- To elucidate the role of the activator-repressor protein (C) in controlling REase expression.
Main Methods:
- Mathematical modeling of the PvuII RM system's regulatory network.
- Experimental validation of model predictions, focusing on gene copy number and protein accumulation.
- Analysis of the nonlinear autoregulatory feedback loop involving the C protein.
Main Results:
- Experimental confirmation of model predictions regarding gene copy number influence on RM system regulation.
- Demonstration of a hysteretic response in REase expression, dependent on C-protein accumulation rates.
- Identification of C-protein accumulation rate as the key factor delaying REase expression.
Conclusions:
- Gene copy number and C-protein accumulation dynamics are critical for regulating type II RM systems.
- Hysteresis in gene expression provides a mechanism for controlling REase activity.
- These findings offer insights into the widespread dissemination and evolutionary success of C-regulated RM systems.
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