Molecular analysis of small RNA and small protein regulation of Escherichia coli stress responses
type: CreativeWork
description: Small RNA (sRNA) regulators control gene expression throughout all domains of life. In bacteria, they typically affect virulence, metabolism, and stress response genes posttranscriptionally through imperfect antisense pairing with their mRNAs. While most sRNAs are non-coding, a small number act as mRNAs themselves by encoding functional proteins. This study examines the regulatory and physiological effects of both a non-coding sRNA, DicF, and the protein product of a dual-function sRNA, SgrS in Eschericha coli. The sRNA SgrS encodes the small 43-amino acid protein SgrT. Both molecules are expressed during glucose-phosphate stress - a bacteriostatic condition in which phosphosugars accumulate in the cell either because of mutations in glycolysis or because of the transport of non-metabolizable glucose analogs such as αMG or 2DG. While both SgrT and SgrS base pairing can independently mitigate glucose-phosphate stress, they do so through distinct mechanisms. SgrS base pairing destabilizes the mRNA of the respective major and minor glucose transporters PtsG and ManXYZ, thereby inhibiting synthesis of additional glucose permeases and restricting further influx of non-metabolizable sugars. In this study we demonstrate that SgrT acts to specifically inhibit the transport activity of preexisting PtsG transporters, but does not affect ManXYZ. We reveal that by targeting PtsG transport activity SgrT not only prevents influx of non-metabolizable αMG, but also overrides inducer exclusion allowing alternative carbon sources to be transported and metabolized during stress. We also uncover the regions of PtsG that are required for SgrT regulation. Although the precise nature of glucose-phosphate stress is not well understood, this work establishes that sugar phosphates are not inherently toxic, but most likely inhibit growth by depleting glycolytic intermediates, as these are expended to transport sugars and not are replenished due to a blockage in glycolysis. Sugar phosphate acc…
abstract: Small RNA (sRNA) regulators control gene expression throughout all domains of life. In bacteria, they typically affect virulence, metabolism, and stress response genes posttranscriptionally through imperfect antisense pairing with their mRNAs. While most sRNAs are non-coding, a small number act as mRNAs themselves by encoding functional proteins. This study examines the regulatory and physiological effects of both a non-coding sRNA, DicF, and the protein product of a dual-function sRNA, SgrS in Eschericha coli. The sRNA SgrS encodes the small 43-amino acid protein SgrT. Both molecules are expressed during glucose-phosphate stress - a bacteriostatic condition in which phosphosugars accumulate in the cell either because of mutations in glycolysis or because of the transport of non-metabolizable glucose analogs such as αMG or 2DG. While both SgrT and SgrS base pairing can independently mitigate glucose-phosphate stress, they do so through distinct mechanisms. SgrS base pairing destabilizes the mRNA of the respective major and minor glucose transporters PtsG and ManXYZ, thereby inhibiting synthesis of additional glucose permeases and restricting further influx of non-metabolizable sugars. In this study we demonstrate that SgrT acts to specifically inhibit the transport activity of preexisting PtsG transporters, but does not affect ManXYZ. We reveal that by targeting PtsG transport activity SgrT not only prevents influx of non-metabolizable αMG, but also overrides inducer exclusion allowing alternative carbon sources to be transported and metabolized during stress. We also uncover the regions of PtsG that are required for SgrT regulation. Although the precise nature of glucose-phosphate stress is not well understood, this work establishes that sugar phosphates are not inherently toxic, but most likely inhibit growth by depleting glycolytic intermediates, as these are expended to transport sugars and not are replenished due to a blockage in glycolysis. Sugar phosphate acc…
author: Lloyd, Chelsea Royal
language: en
keywords: sRNA, small protein, glucose-phosphate stress, SgrS, SgrT, DicF
date published: 2018-09-27T16:30:28Z
date modified: 2026-07-22T22:24:40Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/101691