DNA turnover and mutation in resting cells

Bridges, B.A.

doi:10.1002/bies.950190412

Cited by 41 publications

(15 citation statements)

References 39 publications

(15 reference statements)

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“…It is possible that phenol disturbs the DNA turnover in starving colR mutant bacteria. Indeed, studies of the stationary-phase (adaptive) mutation have revealed that a remarkable DNA turnover is needed for the emergence of mutations in starving populations of bacteria (6). As both transposition and point mutations require DNA synthesis, inhibition of DNA replication by phenol overdose should explain the suppression of mutational processes in starving bacteria.…”

Section: Discussionmentioning

confidence: 99%

The ColRS Two-Component System Regulates Membrane Functions and Protects Pseudomonas putida against Phenol

et al. 2006

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As reported, the two-component system ColRS is involved in two completely different processes. It facilitates the root colonization ability of Pseudomonas fluorescens and is necessary for the Tn4652 transposition-dependent accumulation of phenol-utilizing mutants in Pseudomonas putida. To determine the role of the ColRS system in P. putida, we searched for target genes of response regulator ColR by use of a promoter library. Promoter screening was performed on phenol plates to mimic the conditions under which the effect of ColR on transposition was detected. The library screen revealed the porin-encoding gene oprQ and the alginate biosynthesis gene algD occurring under negative control of ColR. Binding of ColR to the promoter regions of oprQ and algD in vitro confirmed its direct involvement in regulation of these genes. Additionally, the porin-encoding gene ompA PP0773 and the type I pilus gene csuB were also identified in the promoter screen. However, it turned out that ompA PP0773 and csuB were actually affected by phenol and that the influence of ColR on these promoters was indirect. Namely, our results show that ColR is involved in phenol tolerance of P. putida. Phenol MIC measurement demonstrated that a colR mutant strain did not tolerate elevated phenol concentrations. Our data suggest that increased phenol susceptibility is also the reason for inhibition of transposition of Tn4652 in phenol-starving colR mutant bacteria. Thus, the current study revealed the role of the ColRS two-component system in regulation of membrane functionality, particularly in phenol tolerance of P. putida.

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Section: Discussionmentioning

confidence: 99%

The ColRS Two-Component System Regulates Membrane Functions and Protects Pseudomonas putida against Phenol

et al. 2006

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“…Of these DNA-insulting processes, those causing oxidative damage have been shown to be significant in B. subtilis cells under conditions of starvation (45). The ability of RNA polymerase to bypass these and perhaps other types of lesions may result in base misinsertion in the transcript, generating mutant proteins resulting in the appearance of pseudo-prototrophs in nondividing cells (4,22,37). This process was shown to occur in nondividing E. coli cells, where Bregeon et al demonstrated that RNA polymerase can efficiently bypass uracil and 8-oxoG lesions engineered into a luciferase reporter gene (3).…”

Section: Vol 192 2010 Stress-induced Mutagenesis In B Subtilis Celmentioning

confidence: 99%

Transcription-Associated Mutation in Bacillus subtilis Cells under Stress

et al. 2010

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Adaptive (stationary phase) mutagenesis is a phenomenon by which nondividing cells acquire beneficial mutations as a response to stress. Although the generation of adaptive mutations is essentially stochastic, genetic factors are involved in this phenomenon. We examined how defects in a transcriptional factor, previously reported to alter the acquisition of adaptive mutations, affected mutation levels in a gene under selection. The acquisition of mutations was directly correlated to the level of transcription of a defective leuC allele placed under selection. To further examine the correlation between transcription and adaptive mutation, we placed a point-mutated allele, leuC427, under the control of an inducible promoter and assayed the level of reversion to leucine prototrophy under conditions of leucine starvation. Our results demonstrate that the level of Leu ؉ reversions increased significantly in parallel with the induced increase in transcription levels. This mutagenic response was not observed under conditions of exponential growth. Since transcription is a ubiquitous biological process, transcription-associated mutagenesis may influence evolutionary processes in all organisms.The generation of mutations has been traditionally ascribed to spontaneous processes affecting actively growing, dividing cells. Nevertheless, by the mid-1950s, several reports describing mutagenesis in nondividing cells of bacteria, plants, flies, and fungi appeared in the scientific literature (reference 36 and references therein). Much of the initial characterization of this process in bacteria took place in the laboratory of Francis Ryan, who observed Escherichia coli mutants capable of synthesizing histidine arising from his mutant (auxotrophic) cells undergoing prolonged starvation (36) while cell turnover remained undetectable, and DNA replication slowed with increasing time (26). Renewed interest in adaptive mutation was generated when Cairns and coworkers published their work on the generation of Lac ϩ reversions in E. coli cells unable to use the lactose provided as the sole carbon source in a minimal medium (6). This work demonstrated that adaptive mutations can arise as a result of stress rather than from selection of preexisting mutations. The generation of stress-induced Lac ϩ reversions, assayed via a plasmid-borne system, has been studied intensively by several laboratories (reviewed in references 13, 15, and 34; 32) and is dependent on activation of the SOS and/or stress responses. Further studies have also suggested that a subpopulation within the Lac Ϫ stressed cells engage in an exquisitely regulated transient state of hypermutation limited in time and to DNA sites near double-stranded DNA breaks (reviewed in reference 15). Collectively, the results from studies on this system have provided interesting insights into the acquisition of beneficial mutations and demonstrated the role of several genetic factors in the adaptive mutation phenomenon.

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“…Differences in the spectra of mutations have been observed between sets of mutants appearing in starving bacterial populations under selective conditions and in actively growing bacterial cultures (22,32,52,55). The starvation conditions encountered during stationary-phase incubation may permit a transient increase in the mutation rate due to a variety of factors, including decreased fidelity during replication and reduction of DNA repair activity (9,18,58,65; see also references in reference 21). Another mechanism that may increase genetic diversity is the movement of transposable elements (14,56).…”

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confidence: 99%

Different Spectra of Stationary-Phase Mutations in Early-Arising versus Late-Arising Mutants of Pseudomonas putida : Involvement of the DNA Repair Enzyme MutY and the Stationary-Phase Sigma Factor RpoS

et al. 2002

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Stationary-phase mutations occur in populations of stressed, nongrowing, and slowly growing cells and allow mutant bacteria to overcome growth barriers. Mutational processes in starving cells are different from those occurring in growing bacteria. Here, we present evidence that changes in mutational processes also take place during starvation of bacteria. Our test system for selection of mutants based on creation of functional promoters for the transcriptional activation of the phenol degradation genes pheBA in starving Pseudomonas putida enables us to study base substitutions (C-to-A or G-to-T transversions), deletions, and insertions. We observed changes in the spectrum of promoter-creating mutations during prolonged starvation of Pseudomonas putida on phenol minimal plates. One particular C-to-A transversion was the prevailing mutation in starving cells. However, with increasing time of starvation, the importance of this mutation decreased but the percentage of other types of mutations, such as 2-to 3-bp deletions, increased. The rate of transversions was markedly elevated in the P. putida MutY-defective strain. The occurrence of 2-to 3-bp deletions required the stationaryphase sigma factor RpoS, which indicates that some mutagenic pathway is positively controlled by RpoS in P. putida.

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DNA turnover and mutation in resting cells

Cited by 41 publications

References 39 publications

The ColRS Two-Component System Regulates Membrane Functions and Protects Pseudomonas putida against Phenol

The ColRS Two-Component System Regulates Membrane Functions and Protects Pseudomonas putida against Phenol

Transcription-Associated Mutation in Bacillus subtilis Cells under Stress

Different Spectra of Stationary-Phase Mutations in Early-Arising versus Late-Arising Mutants of Pseudomonas putida : Involvement of the DNA Repair Enzyme MutY and the Stationary-Phase Sigma Factor RpoS

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