Expression noise facilitates the evolution of gene regulation

Area of Science:

• Molecular biology
• Evolutionary biology
• Systems biology

Background:

• Gene regulatory interactions are assumed to be finely tuned.
• The evolution of accurate gene regulation from a non-regulated state is not well understood.
• Gene expression noise is often considered an impediment to the evolution of accurate gene regulation.

Purpose of the Study:

• To investigate the evolution of accurate gene regulation.
• To understand the role of gene expression noise in this process.
• To challenge the assumption that natural selection always lowers gene expression noise.

Main Methods:

• Evolving synthetic Escherichia coli promoters de novo.
• Analyzing the noise levels of evolved promoters.
• Developing a general theory for gene expression noise and regulation.

Main Results:

• Synthetic promoters exhibit low noise by default.
• Selection appears to increase noise levels in highly regulated E. coli promoters.
• Gene expression noise propagation acts as a rudimentary regulatory mechanism.

Conclusions:

• The evolution of accurate gene regulation may involve an increase in noise, not just a decrease.
• Gene expression noise is not solely a hindrance but can facilitate regulatory evolution.
• A new theoretical framework explains the interplay between noise and regulation.