Abstract

Genetically identical individuals in bacterial populations can display significant phenotypic variability. This variability can be functional, for example by allowing a fraction of stress prepared cells to survive an otherwise lethal stress. The optimal fraction of stress prepared cells depends on environmental conditions. However, how bacterial populations modulate their level of phenotypic variability remains unclear. Here we show that the alternative sigma factor σV circuit in Bacillus subtilis generates functional phenotypic variability that can be tuned by stress level, environmental history and genetic perturbations. Using single‐cell time‐lapse microscopy and microfluidics, we find the fraction of cells that immediately activate σV under lysozyme stress depends on stress level and on a transcriptional memory of previous stress. Iteration between model and experiment reveals that this tunability can be explained by the autoregulatory feedback structure of the sigV operon. As predicted by the model, genetic perturbations to the operon also modulate the response variability. The conserved sigma‐anti‐sigma autoregulation motif is thus a simple mechanism for bacterial populations to modulate their heterogeneity based on their environment.

Details

Title
Tunable phenotypic variability through an autoregulatory alternative sigma factor circuit
Author
Schwall, Christian P 1 ; Loman, Torkel E 1 ; Martins, Bruno M C 2 ; Cortijo, Sandra 1 ; Villava, Casandra 1 ; Kusmartsev, Vassili 1 ; Livesey, Toby 1 ; Saez, Teresa 1 ; Locke, James C W 1   VIAFID ORCID Logo 

 Sainsbury Laboratory, University of Cambridge, Cambridge, UK 
 Sainsbury Laboratory, University of Cambridge, Cambridge, UK; School of Life Sciences, University of Warwick, Coventry, UK 
Section
Articles
Publication year
2021
Publication date
Jul 2021
Publisher
EMBO Press
e-ISSN
17444292
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2555856001
Copyright
© 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.