Stochastic Analysis Demonstrates the Dual Role of Hfq in ChaperoningE. coliSugar Shock Response

Abstract

<jats:title>Abstract</jats:title><jats:p>Small RNAs (sRNAs) play a crucial role in the regulation of bacterial gene expression by silencing the translation of target mRNAs. SgrS is an sRNA that relieves glucose–phosphate stress, or “sugar shock” in <jats:italic>E. coli</jats:italic>. The power of single cell measurements is their ability to obtain population level statistics that illustrate cell–to–cell variation. Here, we utilize single molecule super–resolution microscopy in single <jats:italic>E. coli</jats:italic> cells coupled with stochastic modeling to analyze glucose–phosphate stress regulation by SgrS. We present a kinetic model that captures the combined effects of transcriptional regulation, gene replication and chaperone mediated RNA silencing in the SgrS regulatory network. This more complete kinetic description, simulated stochastically, recapitulates experimentally observed cellular heterogeneity and is used to describe the dynamics of SgrS stabilization by the chaperone protein Hfq.</jats:p>