Stress-Induced Mutation Rates Show a Sigmoidal and Saturable Increase Due to the RpoS Sigma Factor in <i>Escherichia coli</i>

Maharjan, Ram; Ferenci, Thomas

doi:10.1534/genetics.114.170258

Cited by 10 publications

(17 citation statements)

References 31 publications

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“…Recently, the Ferenci laboratory showed that varying RpoS levels gives rise to different mutation rates and patterns. Increasing the levels of RpoS leads to a decrease of MutS levels and an increase of DNAP IV levels and vice versa [ 90 , 92 , 93 ]. These observations are highly relevant for the isolation of strains with improved protein production characteristics, since, during their isolation, cells are exposed to stress caused by the production of proteins.…”

Section: Dna Integrity and Mutagenesismentioning

confidence: 99%

Isolating Escherichia coli strains for recombinant protein production

Schlegel

Genevaux

Gier

2016

Cell. Mol. Life Sci.

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Escherichia coli has been widely used for the production of recombinant proteins. To improve protein production yields in E. coli, directed engineering approaches have been commonly used. However, there are only few reported examples of the isolation of E. coli protein production strains using evolutionary approaches. Here, we first give an introduction to bacterial evolution and mutagenesis to set the stage for discussing how so far selection- and screening-based approaches have been used to isolate E. coli protein production strains. Finally, we discuss how evolutionary approaches may be used in the future to isolate E. coli strains with improved protein production characteristics.

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Section: Dna Integrity and Mutagenesismentioning

confidence: 99%

Isolating Escherichia coli strains for recombinant protein production

Schlegel

Genevaux

Gier

2016

Cell. Mol. Life Sci.

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“…The ability to measure mutation rates at fixed growth rates allows one to test some of the core assumptions on the environment-mutation relationship. One common notion in studies of SIM is the regulatory requirement for RpoS (Lombardo et al, 2004;Storvik and Foster, 2010;Maharjan and Ferenci, 2014). Essentially all external stresses induce elevated levels of RpoS, as does stationary phase and reduced growth rate (Notley-McRobb et al, 2002;Hengge, 2011).…”

Section: Correlation Of Mutation Rates With the General Stress Responmentioning

confidence: 99%

“…In this century, however, the MES assumption of mutational randomness and unchanging mutation rates has been challenged (Yampolsky and Stoltzfus, ; Ninio, ; Fitzgerald and Rosenberg, ). A factor in the changing views on the role of environments in mutation rates was the emerging evidence for stress‐induced mutagenesis (SIM), mainly using Escherichia coli as the model organism (Foster, ; Galhardo et al ., ; Rosenberg et al ., ; Maharjan and Ferenci, , ).…”

Section: Introduction To the Stress–mutation Relationshipmentioning

confidence: 99%

Irregularities in genetic variation and mutation rates with environmental stresses

Ferenci

2019

Environmental Microbiology

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Summary The appearance of new mutations is determined by the equilibrium between DNA error formation and repair. In bacteria like Escherichia coli, stresses are thought shift this balance towards increased mutagenesis. Recent findings, however, suggest a very uneven relationship between stress and mutations. Only a subset of stressful environments increase the net rate of mutation and different forms of nutritional stress (such as oxygen, carbon or phosphorus limitations) result in markedly different mutation rates after similar reductions in growth rate. Moreover, different stresses result in altered mutational spectra, with some increasing transposition and others increasing indel formation. Single‐base substitution rates are lower with some stresses than in unstressed bacteria. Indeed, changes to the mix of mutations with stress are more widespread than a marked increase in net mutation rate. Much remains to be learned on how environments have unique mutational signatures and why some stresses are more mutagenic than others. Even beyond stress‐induced genetic variation, the fundamental unresolved question in the stress–mutation relationship is the adaptive value of different types of mutations and mutation rates; is transposition, for example, more advantageous under anaerobic conditions? It remains to be investigated whether stress‐specific genetic variation impacts on evolvability differentially in distinct environments.

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“…Like amplification within the F , the higher copy number increases the number of targets and would lead to an elevated revertant frequency. Other recent studies have argued in favor of stress mutagenesis by showing that mutation rates can be elevated threefold to fourfold without selection for growth fitness by controlling the intracellular concentration of the transcription factor RpoS [31], which had earlier been reported to be required for adaptive stress mutagenesis [21]. Thus, the debate continues owing to the difficulty of cleanly differentiating whether the elevated revertant frequencies observed after long incubation on selective media are ascribable to stress-induced mutagenesis [19,32] that may involve error-prone DNA synthesis during recombination in nongrowing cells [33] or to the growth limitation serving exclusively as a selective agent for revertants that arise at conventional mutation rates [30,[34][35][36].…”

Section: Tablementioning

confidence: 99%