Power-law scaling in protein synthesis of a stochastic regulon

TL;DR

This study reveals that protein expression levels of the lamB gene in E. coli follow a power-law distribution, with the exponent influenced by growth conditions, highlighting stochastic gene expression's role in bacterial populations.

Contribution

The paper introduces a heuristic model linking power-law exponents in protein distribution to protein production rates under different growth conditions.

Findings

LamB receptor distribution follows a scale-invariant power-law.

Exponent of the power-law depends on growth conditions.

Model relates power-law exponent to protein production rate.

Abstract

We investigate the protein expression pattern of the lamB gene in Escherichia coli LE392. The gene product LamB is an important membrane protein for maltose transport into cells but it is also exploited by bacteriophage lambda for infection. Although our bacterial population is clonal, stochastic gene expression leads to a majority population with a large receptor number and a minority population with a small receptor number. We find that the LamB receptor distribution p(n) of the small-n population is scale invariant with the exponent depending on growth conditions. A heuristic model is proposed that relates the observed exponent to the protein production rate.