The Influence of Decoys on the Noise and Dynamics of Gene Expression

TL;DR

This paper investigates how decoy DNA binding sites influence gene expression noise and dynamics, revealing their role in noise reduction, timing of steady state achievement, and epigenetic switching behavior.

Contribution

It demonstrates that decoy sites buffer noise to a Poisson limit and modulate gene expression dynamics, providing new insights into gene regulation mechanisms.

Findings

Decoys decrease noise in unbound protein numbers to a Poisson limit.

Decoys linearly increase the time to reach steady state.

Decoys exponentially increase the time for epigenetic switching.

Abstract

Many transcription factors bind to DNA with a remarkable lack of specificity, so that regulatory binding sites compete with an enormous number of non-regulatory 'decoy' sites. For an auto-regulated gene, we show decoy sites decrease noise in the number of unbound proteins to a Poisson limit that results from binding and unbinding. This noise buffering is optimized for a given protein concentration when decoys have a 1/2 probability of being occupied. Decoys linearly increase the time to approach steady state and exponentially increase the time to switch epigenetically between bistable states.