scholarly journals Adaptation to DNA damage as a bet-hedging mechanism in a fluctuating environment

2021 ◽  
Vol 8 (8) ◽  
pp. 210460
Author(s):  
Pierre Roux ◽  
Delphine Salort ◽  
Zhou Xu
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Division ◽  
Cell Survival ◽  
Genome Instability ◽  
Population Level ◽  
Signalling Pathway ◽  
Genome Integrity ◽  
Dna Damage Checkpoint ◽  
Bet Hedging

In response to DNA damage, efficient repair is essential for cell survival and genome integrity. In eukaryotes, the DNA damage checkpoint is a signalling pathway that coordinates this response and arrests the cell cycle to provide time for repair. However, when repair fails or when the damage is not repairable, cells can eventually bypass the DNA damage checkpoint and undergo cell division despite persistent damage, a process called adaptation to DNA damage. Interestingly, adaptation occurs with a delayed timing compared with repair and shows a large variation in time, two properties that may provide a survival advantage at the population level without interfering with repair. Here, we explore this idea by mathematically modelling cell survival in response to DNA damage and focusing on adaptation parameters. We find that the delayed adaptation timing indeed maximizes survival, but its heterogeneity is beneficial only in a fluctuating damage-inducing environment. Finally, we show that adaptation does not only contribute to survival but also to genome instability and mutations, which might represent another criterion for its selection throughout evolution. Overall, we propose that adaptation can act as a bet-hedging mechanism for cell survival in response to DNA damage.

scholarly journals Adaptation to DNA damage as a bet-hedging mechanism in a fluctuating environment

2021 ◽  
Author(s):  
Pierre Roux ◽  
Delphine Salort ◽  
Zhou Xu
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Division ◽  
Cell Survival ◽  
Genome Instability ◽  
Population Level ◽  
Signalling Pathway ◽  
Genome Integrity ◽  
Dna Damage Checkpoint ◽  
Bet Hedging

AbstractIn response to DNA damage, efficient repair is essential for cell survival and genome integrity. In eukaryotes, the DNA damage checkpoint is a signalling pathway that coordinates this response and arrests the cell cycle to provide time for repair. However, when repair fails or when the damage is not repairable, cells can eventually bypass the DNA damage checkpoint and undergo cell division despite persistent damage, a process called adaptation to DNA damage. Interestingly, adaptation occurs with a delayed timing compared to repair and shows a large variation in time, two properties that may provide a survival advantage at the population level without interfering with repair. Here, we explore this idea by mathematically modelling cell survival in response to DNA damage and focusing on adaptation parameters. We find that the delayed adaptation timing indeed maximizes survival, but its heterogeneity is beneficial only in a fluctuating damage-inducing environment. Finally, we show that adaptation does not only contribute to survival but also to genome instability and mutations, which might represent another criterion for its selection through-out evolution. Overall, we propose that adaptation can act as a bet-hedging mechanism for cell survival in response to DNA damage.

scholarly journals Regulation of Cell Division in Bacteria by Monitoring Genome Integrity and DNA Replication Status

2019 ◽  
Vol 202 (2) ◽  
Author(s):  
Peter E. Burby ◽  
Lyle A. Simmons
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Division ◽  
Dna Replication ◽  
Cell Cycle Progression ◽  
Genome Instability ◽  
Sos Response ◽  
Bacterial Cells ◽  
Cycle Progression ◽  
Content Type

ABSTRACT All organisms regulate cell cycle progression by coordinating cell division with DNA replication status. In eukaryotes, DNA damage or problems with replication fork progression induce the DNA damage response (DDR), causing cyclin-dependent kinases to remain active, preventing further cell cycle progression until replication and repair are complete. In bacteria, cell division is coordinated with chromosome segregation, preventing cell division ring formation over the nucleoid in a process termed nucleoid occlusion. In addition to nucleoid occlusion, bacteria induce the SOS response after replication forks encounter DNA damage or impediments that slow or block their progression. During SOS induction, Escherichia coli expresses a cytoplasmic protein, SulA, that inhibits cell division by directly binding FtsZ. After the SOS response is turned off, SulA is degraded by Lon protease, allowing for cell division to resume. Recently, it has become clear that SulA is restricted to bacteria closely related to E. coli and that most bacteria enforce the DNA damage checkpoint by expressing a small integral membrane protein. Resumption of cell division is then mediated by membrane-bound proteases that cleave the cell division inhibitor. Further, many bacterial cells have mechanisms to inhibit cell division that are regulated independently from the canonical LexA-mediated SOS response. In this review, we discuss several pathways used by bacteria to prevent cell division from occurring when genome instability is detected or before the chromosome has been fully replicated and segregated.

scholarly journals Escherichia coli cyclomodulin Cif induces G2arrest of the host cell cycle without activation of the DNA-damage checkpoint-signalling pathway

2006 ◽  
Vol 8 (12) ◽  
pp. 1910-1921 ◽  
Author(s):  
Frédéric Taieb ◽  
Jean-Philippe Nougayrède ◽  
Claude Watrin ◽  
Ascel Samba-Louaka ◽  
Eric Oswald
Keyword(s):  
Escherichia Coli ◽  
Cell Cycle ◽  
Dna Damage ◽  
Host Cell ◽  
Signalling Pathway ◽  
Dna Damage Checkpoint

scholarly journals The Last Chance Saloon

2021 ◽  
Vol 9 ◽  
Author(s):  
Ye Hong ◽  
Hongtao Zhang ◽  
Anton Gartner
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Chromosome Segregation ◽  
Cell Cycle Progression ◽  
Genome Instability ◽  
Genome Integrity ◽  
Cycle Progression ◽  
Chromosome Fragmentation ◽  
C Elegans ◽  
Chromatin Bridges

Accurate chromosome segregation requires the removal of all chromatin bridges, which link chromosomes before cell division. When chromatin bridges fail to be removed, cell cycle progression may halt, or cytokinesis failure and ensuing polyploidization may occur. Conversely, the inappropriate severing of chromatin bridges leads to chromosome fragmentation, excessive genome instability at breakpoints, micronucleus formation, and chromothripsis. In this mini-review, we first describe the origins of chromatin bridges, the toxic processing of chromatin bridges by mechanical force, and the TREX1 exonuclease. We then focus on the abscission checkpoint (NoCut) which can confer a transient delay in cytokinesis progression to facilitate bridge resolution. Finally, we describe a recently identified mechanism uncovered in C. elegans where the conserved midbody associated endonuclease LEM-3/ANKLE1 is able to resolve chromatin bridges generated by various perturbations of DNA metabolism at the final stage of cell division. We also discuss how LEM-3 dependent chromatin bridge resolution may be coordinated with abscission checkpoint (NoCut) to achieve an error-free cleavage, therefore acting as a “last chance saloon” to facilitate genome integrity and organismal survival.

scholarly journals C. elegans THSC/TREX-2 deficiency causes replication stress and genome instability

2021 ◽  
Author(s):  
Angelina Zheleva ◽  
Lola P Camino ◽  
Nuria Fernández-Fernández ◽  
María García-Rubio ◽  
Peter Askjaer ◽  
...  
Keyword(s):  
Dna Damage ◽  
Damage Accumulation ◽  
Genome Instability ◽  
Underlying Mechanism ◽  
Rnase H ◽  
Genome Integrity ◽  
Dna Damage Checkpoint ◽  
C Elegans ◽  
Mrnp Biogenesis

Transcription is an essential process of DNA metabolism, yet it makes DNA more susceptible to DNA damage. THSC/TREX-2 is a conserved eukaryotic protein complex with a key role in mRNP biogenesis and maturation that prevents genome instability. One source of such instability is linked to transcription as shown in yeast and human cells, but the underlying mechanism and whether is universal is still unclear. To get further insight in the putative role of THSC/TREX-2 in genome integrity we have used Caenorhabditis elegans mutants of the THP-1 and DSS-1 members of THSC/TREX-2. These mutants show similar defective meiosis, DNA damage accumulation and activation of the DNA damage checkpoint. However, they differ regarding replication defects as determined by dUTP incorporation in the germline. Interestingly, this specific thp-1 phenotype can be partially rescued by overexpression of RNase H. Furthermore, both mutants show a mild increase in the H3S10P mark previously shown to be linked to DNA-RNA hybrid-mediated genome instability. These data support the view that both THSC/TREX-2 factors prevent transcription-associated DNA damage derived from DNA-RNA hybrid accumulation by separate means.

scholarly journals The Ulp2 SUMO Protease Is Required for Cell Division following Termination of the DNA Damage Checkpoint

2007 ◽  
Vol 27 (19) ◽  
pp. 6948-6961 ◽  
Author(s):  
David C. Schwartz ◽  
Rachael Felberbaum ◽  
Mark Hochstrasser
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Division ◽  
Strand Break ◽  
Dna Damage Checkpoint ◽  
Checkpoint Signaling ◽  
Sumo Protease ◽  
Checkpoint Pathway ◽  
Show Evidence ◽  
A Cell

ABSTRACT Eukaryotic genome integrity is maintained via a DNA damage checkpoint that recognizes DNA damage and halts the cell cycle at metaphase, allowing time for repair. Checkpoint signaling is eventually terminated so that the cell cycle can resume. How cells restart cell division following checkpoint termination is poorly understood. Here we show that the SUMO protease Ulp2 is required for resumption of cell division following DNA damage-induced arrest in Saccharomyces cerevisiae, although it is not required for DNA double-strand break repair. The Rad53 branch of the checkpoint pathway generates a signal countered by Ulp2 activity following DNA damage. Interestingly, unlike previously characterized adaptation mutants, ulp2Δ mutants do not show persistent Rad53 phosphorylation following DNA damage, suggesting checkpoint signaling has been terminated and no longer asserts an arrest in these cells. Using Cdc14 localization as a cell cycle indicator, we show that nearly half of cells lacking Ulp2 can escape a checkpoint-induced metaphase arrest despite their inability to divide again. Moreover, half of permanently arrested ulp2Δ cells show evidence of an aberrant mitotic spindle, suggesting that Ulp2 is required for proper spindle dynamics during cell cycle resumption following a DNA damage-induced cell cycle arrest.

scholarly journals DNA damage checkpoint activation impairs chromatin homeostasis and promotes mitotic catastrophe during aging

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Matthew M Crane ◽  
Adam E Russell ◽  
Brent J Schafer ◽  
Ben W Blue ◽  
Riley Whalen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Genome Instability ◽  
Cell Cycle Checkpoints ◽  
Mitotic Catastrophe ◽  
Dna Damage Checkpoint ◽  
Age Related ◽  
Altered Cell ◽  
Histone Transcription ◽  
Cell Cycle Dynamics

Genome instability is a hallmark of aging and contributes to age-related disorders such as cancer and Alzheimer’s disease. The accumulation of DNA damage during aging has been linked to altered cell cycle dynamics and the failure of cell cycle checkpoints. Here, we use single cell imaging to study the consequences of increased genomic instability during aging in budding yeast and identify striking age-associated genome missegregation events. This breakdown in mitotic fidelity results from the age-related activation of the DNA damage checkpoint and the resulting degradation of histone proteins. Disrupting the ability of cells to degrade histones in response to DNA damage increases replicative lifespan and reduces genomic missegregations. We present several lines of evidence supporting a model of antagonistic pleiotropy in the DNA damage response where histone degradation, and limited histone transcription are beneficial to respond rapidly to damage but reduce lifespan and genomic stability in the long term.

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