Competition and evolutionary selection among core regulatory motifs in gene expression control

Area of Science:

• Genetics
• Evolutionary Biology
• Systems Biology

Background:

• Gene products can be detrimental in different environments, necessitating regulatory mechanisms.
• These regulatory schemes incur bioenergetic costs.
• Environmental changes and mutations drive the evolution of gene regulation.

Purpose of the Study:

• To investigate the evolutionary advantage of autoregulation in gene expression.
• To determine how mutation and time-varying selection influence regulatory schemes.
• To understand the impact of positive versus negative feedback in autoregulation.

Main Methods:

• Analysis of transcription networks in multiple model organisms.
• Modeling of gene regulatory circuits under varying selective pressures.
• Comparative analysis of autoregulation with other regulatory motifs.

Main Results:

• Autoregulation generally provides an advantage in environments with mutation and fluctuating selection.
• The dominance of positive or negative feedback in autoregulation is dictated by the demand for the target gene product.
• Self-repression limits loss-of-function mutations, while self-activation promotes their spread.
• Reduced bioenergetic cost may favor autoregulation in transcription factors.

Conclusions:

• Autoregulation's impact on population dynamics and evolution differs significantly between positive and negative feedback motifs.
• Findings can guide the design of robust synthetic gene circuits.
• Understanding regulatory costs is crucial for evolutionary adaptation.