# Sub-cellular mRNA localization modulates the regulation of gene expression by small RNAs in bacteria

## TL;DR

This paper explores how the sub-cellular localization of mRNAs influences bacterial gene regulation by small RNAs, revealing that spatial distribution affects regulatory thresholds and target hierarchy, with implications for modeling gene circuits.

## Contribution

It introduces a mathematical model demonstrating the impact of mRNA localization on sRNA-mediated regulation and target hierarchy in bacteria.

## Key findings

- mRNA localization alters sRNA response thresholds
- sub-cellular organization modulates target hierarchy
- spatial heterogeneity influences gene regulation dynamics

## Abstract

Small non-coding RNAs can exert significant regulatory activity on gene expression in bacteria. In recent years, substantial progress has been made in understanding bacterial gene expression by sRNAs. However, recent findings that demonstrate that families of mRNAs show non-trivial sub-cellular distributions raise the question of how localization may affect the regulatory activity of sRNAs. Here we address this question within a simple mathematical model. We show that the non-uniform spatial distributions of mRNA can alter the threshold-linear response that characterizes sRNAs that act stoichiometrically, and modulate the hierarchy among targets co-regulated by the same sRNA. We also identify conditions where the sub-cellular organization of cofactors in the sRNA pathway can induce spatial heterogeneity on sRNA targets. Our results suggest that under certain conditions, interpretation and modeling of natural and synthetic gene regulatory circuits need to take into account the spatial organization of the transcripts of participating genes.