Adaptive tuning of mutation rates allows fast response to lethal stress in Escherichia coli
Abstract
While specific mutations allow organisms to adapt to stressful environments, most changes in an organism's DNA negatively impact fitness. The mutation rate is therefore strictly regulated and often considered a slowly-evolving parameter. In contrast, we demonstrate an unexpected flexibility in cellular mutation rates as a response to changes in selective pressure. We show that hypermutation independently evolves when different Escherichia coli cultures adapt to high ethanol stress. Furthermore, hypermutator states are transitory and repeatedly alternate with decreases in mutation rate. Specifically, population mutation rates rise when cells experience higher stress and decline again once cells are adapted. Interestingly, we identified cellular mortality as the major force driving the quick evolution of mutation rates. Together, these findings show how organisms balance robustness and evolvability and help explain the prevalence of hypermutation in various settings, ranging from emergence of antibiotic resistance in microbes to cancer relapses upon chemotherapy.
Data availability
-
Highly ethanol tolerant Escherichia coli with hypermutation phenotypePublicly available at the NCBI SRA repository (Accession no: PRJNA344553).
Article and author information
Author details
Funding
Agentschap voor Innovatie door Wetenschap en Technologie (Strategic Basic Research Fellowship,121525)
- Toon Swings
Fonds Wetenschappelijk Onderzoek (Postdoctoral Fellowship,1249117N)
- Karin Voordeckers
Onderzoeksraad, KU Leuven (IDO/09/010)
- Kevin J Verstrepen
- Jan Michiels
Onderzoeksraad, KU Leuven (IDO/13/008)
- Jan Michiels
Onderzoeksraad, KU Leuven (CREA/13/019)
- Maarten Fauvart
Onderzoeksraad, KU Leuven (DBOF/12/035; DBOF/14/049)
- Kevin J Verstrepen
- Jan Michiels
Fonds Wetenschappelijk Onderzoek (KAN2014 1.5.222.14)
- Maarten Fauvart
Onderzoeksraad, KU Leuven (PF/10/010)
- Kevin J Verstrepen
- Jan Michiels
Interuniversity Attraction Poles-Belgian Science Policy Office (IAP P7/28)
- Jan Michiels
H2020 European Research Council (241426)
- Kevin J Verstrepen
Human Frontier Science Program (RGP0050/2013)
- Kevin J Verstrepen
Fonds Wetenschappelijk Onderzoek (G047112N)
- Jan Michiels
Vlaams Instituut voor Biotechnologie
- Kevin J Verstrepen
European Molecular Biology Organization
- Kevin J Verstrepen
Fonds Wetenschappelijk Onderzoek (Postdoctoral Fellowship,12O1917N)
- Bram Van den Bergh
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2017, Swings et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 8,710
- views
-
- 1,170
- downloads
-
- 91
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Further reading
-
- Cell Biology
- Microbiology and Infectious Disease
Zika virus (ZIKV) infection causes significant human disease that, with no approved treatment or vaccine, constitutes a major public health concern. Its life cycle entirely relies on the cytoplasmic fate of the viral RNA genome (vRNA) through a fine-tuned equilibrium between vRNA translation, replication, and packaging into new virions, all within virus-induced replication organelles (vROs). In this study, with an RNA interference (RNAi) mini-screening and subsequent functional characterization, we have identified insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) as a new host dependency factor that regulates vRNA synthesis. In infected cells, IGF2BP2 associates with viral NS5 polymerase and redistributes to the perinuclear viral replication compartment. Combined fluorescence in situ hybridization-based confocal imaging, in vitro binding assays, and immunoprecipitation coupled to RT-qPCR showed that IGF2BP2 directly interacts with ZIKV vRNA 3’ nontranslated region. Using ZIKV sub-genomic replicons and a replication-independent vRO induction system, we demonstrated that IGF2BP2 knockdown impairs de novo vRO biogenesis and, consistently, vRNA synthesis. Finally, the analysis of immunopurified IGF2BP2 complex using quantitative mass spectrometry and RT-qPCR revealed that ZIKV infection alters the protein and RNA interactomes of IGF2BP2. Altogether, our data support that ZIKV hijacks and remodels the IGF2BP2 ribonucleoprotein complex to regulate vRO biogenesis and vRNA neosynthesis.
-
- Microbiology and Infectious Disease
Bacillus velezensis is a species of Bacillus that has been widely investigated because of its broad-spectrum antimicrobial activity. However, most studies on B. velezensis have focused on the biocontrol of plant diseases, with few reports on antagonizing Salmonella Typhimurium infections. In this investigation, it was discovered that B. velezensis HBXN2020, which was isolated from healthy black pigs, possessed strong anti-stress and broad-spectrum antibacterial activity. Importantly, B. velezensis HBXN2020 did not cause any adverse side effects in mice when administered at various doses (1×107, 1×108, and 1×109 CFU) for 14 days. Supplementing B. velezensis HBXN2020 spores, either as a curative or preventive measure, dramatically reduced the levels of S. Typhimurium ATCC14028 in the mice’s feces, ileum, cecum, and colon, as well as the disease activity index (DAI), in a model of infection caused by this pathogen in mice. Additionally, supplementing B. velezensis HBXN2020 spores significantly regulated cytokine levels (Tnfa, Il1b, Il6, and Il10) and maintained the expression of tight junction proteins and mucin protein. Most importantly, adding B. velezensis HBXN2020 spores to the colonic microbiota improved its stability and increased the amount of beneficial bacteria (Lactobacillus and Akkermansia). All together, B. velezensis HBXN2020 can improve intestinal microbiota stability and barrier integrity and reduce inflammation to help treat infection by S. Typhimurium.