The Low Noise Limit in Gene Expression

Area of Science:

• Molecular Biology
• Systems Biology
• Biophysics

Background:

• Protein noise measurements are crucial for understanding biophysical parameters in gene expression.
• Current noise analyses often conflict with directly measured parameters, indicating underlying analytical issues.

Purpose of the Study:

• To resolve inconsistencies between protein noise measurements and directly measured biophysical parameters.
• To investigate the role of translational bursting in setting the low noise limit of gene expression.

Main Methods:

• Analysis of genome-wide translational efficiency variations.
• Comparison of noise patterns in gene expression data, specifically in E. coli.

Main Results:

• Inconsistencies in noise analysis stem from assuming invariant translation rates and overlooking translational bursting.
• Systematic variations in translational efficiency, not constitutive extrinsic noise, control the low noise limit.
• Identified two distinct gene expression noise patterns: a global floor from bursting and high noise in select genes.

Conclusions:

• Translational bursting variability is a key determinant of the low noise limit in gene expression.
• Constitutive extrinsic noise plays a minor role when translational efficiency varies systematically.
• Gene expression exhibits distinct noise patterns influenced by bursting mechanisms.