Dynamic competition between transcription initiation and repression: Role of nonequilibrium steps in cell-to-cell heterogeneity

TL;DR

This paper investigates how nonequilibrium steps in transcription initiation influence cell-to-cell heterogeneity, revealing that such steps can significantly increase transcriptional noise even in weak promoters.

Contribution

It demonstrates that nonequilibrium steps in transcription initiation systematically enhance transcriptional noise and heterogeneity in bacterial populations.

Findings

Nonequilibrium steps increase transcriptional noise.

Weak promoters can produce substantial noise due to nonequilibrium effects.

Cell-to-cell heterogeneity is modulated by the dynamics of transcription initiation.

Abstract

Transcriptional repression may cause transcriptional noise by a competition between repressor and RNA polymerase binding. Although promoter activity is often governed by a single limiting step, we argue here that the size of the noise strongly depends on whether this step is the initial equilibrium binding or one of the subsequent unidirectional steps. Overall, we show that nonequilibrium steps of transcription initiation systematically increase the cell-to-cell heterogeneity in bacterial populations. In particular, this allows also weak promoters to give substantial transcriptional noise.