scholarly journals Persistent broken chromosome inheritance drives genome instability

2020 ◽  
Author(s):  
Chen-Chun Pai ◽  
Samuel C. Durley ◽  
Wei-Chen Cheng ◽  
Nien-Yi Chiang ◽  
Boon-Yu Wee ◽  
...  

AbstractPersistent DNA damage arising from unrepaired broken chromosomes or telomere loss can promote DNA damage checkpoint adaptation, and cell cycle progression, thereby increasing cell survival but also genome instability. However, the nature and extent of such instability is unclear. We show, using Schizosaccharomyces pombe, that inherited broken chromosomes, arising from failed homologous recombination repair, are subject to cycles of segregation, DNA replication and extensive end-processing, termed here SERPent cycles, by daughter cells, over multiple generations. Following Chk1 loss these post-adaptive cycles continue until extensive processing through inverted repeats promotes annealing, fold-back inversion and a spectrum of chromosomal rearrangements, typically isochromosomes, or chromosome loss, in the resultant population. These findings explain how persistent DNA damage drives widespread genome instability, with implications for punctuated evolution, genetic disease and tumorigenesis.One Sentence SummaryReplication and processing of inherited broken chromosomes drives chromosomal instability.

2019 ◽  
Vol 202 (2) ◽  
Author(s):  
Peter E. Burby ◽  
Lyle A. Simmons

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.


2001 ◽  
Vol 21 (5) ◽  
pp. 1710-1718 ◽  
Author(s):  
David J. Galgoczy ◽  
David P. Toczyski

ABSTRACT Despite the fact that eukaryotic cells enlist checkpoints to block cell cycle progression when their DNA is damaged, cells still undergo frequent genetic rearrangements, both spontaneously and in response to genotoxic agents. We and others have previously characterized a phenomenon (adaptation) in which yeast cells that are arrested at a DNA damage checkpoint eventually override this arrest and reenter the cell cycle, despite the fact that they have not repaired the DNA damage that elicited the arrest. Here, we use mutants that are defective in checkpoint adaptation to show that adaptation is important for achieving the highest possible viability after exposure to DNA-damaging agents, but it also acts as an entrée into some forms of genomic instability. Specifically, the spontaneous and X-ray-induced frequencies of chromosome loss, translocations, and a repair process called break-induced replication occur at significantly reduced rates in adaptation-defective mutants. This indicates that these events occur after a cell has first arrested at the checkpoint and then adapted to that arrest. Because malignant progression frequently involves loss of genes that function in DNA repair, adaptation may promote tumorigenesis by allowing genomic instability to occur in the absence of repair.


2019 ◽  
Vol 116 (39) ◽  
pp. 19464-19473 ◽  
Author(s):  
Stella Pappa ◽  
Natalia Padilla ◽  
Simona Iacobucci ◽  
Marta Vicioso ◽  
Elena Álvarez de la Campa ◽  
...  

Histone H3 lysine 9 methylation (H3K9me) is essential for cellular homeostasis; however, its contribution to development is not well established. Here, we demonstrate that the H3K9me2 demethylase PHF2 is essential for neural progenitor proliferation in vitro and for early neurogenesis in the chicken spinal cord. Using genome-wide analyses and biochemical assays we show that PHF2 controls the expression of critical cell cycle progression genes, particularly those related to DNA replication, by keeping low levels of H3K9me3 at promoters. Accordingly, PHF2 depletion induces R-loop accumulation that leads to extensive DNA damage and cell cycle arrest. These data reveal a role of PHF2 as a guarantor of genome stability that allows proper expansion of neural progenitors during development.


2019 ◽  
Vol 218 (12) ◽  
pp. 3892-3902 ◽  
Author(s):  
Bennie Lemmens ◽  
Arne Lindqvist

The core function of the cell cycle is to duplicate the genome and divide the duplicated DNA into two daughter cells. These processes need to be carefully coordinated, as cell division before DNA replication is complete leads to genome instability and cell death. Recent observations show that DNA replication, far from being only a consequence of cell cycle progression, plays a key role in coordinating cell cycle activities. DNA replication, through checkpoint kinase signaling, restricts the activity of cyclin-dependent kinases (CDKs) that promote cell division. The S/G2 transition is therefore emerging as a crucial regulatory step to determine the timing of mitosis. Here we discuss recent observations that redefine the coupling between DNA replication and cell division and incorporate these insights into an updated cell cycle model for human cells. We propose a cell cycle model based on a single trigger and sequential releases of three molecular brakes that determine the kinetics of CDK activation.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Lionel Condé ◽  
Yulemi Gonzalez Quesada ◽  
Florence Bonnet-Magnaval ◽  
Rémy Beaujois ◽  
Luc DesGroseillers

AbstractBackgroundStaufen2 (STAU2) is an RNA binding protein involved in the posttranscriptional regulation of gene expression. In neurons, STAU2 is required to maintain the balance between differentiation and proliferation of neural stem cells through asymmetric cell division. However, the importance of controlling STAU2 expression for cell cycle progression is not clear in non-neuronal dividing cells. We recently showed that STAU2 transcription is inhibited in response to DNA-damage due to E2F1 displacement from theSTAU2gene promoter. We now study the regulation of STAU2 steady-state levels in unstressed cells and its consequence for cell proliferation.ResultsCRISPR/Cas9-mediated and RNAi-dependent STAU2 depletion in the non-transformed hTERT-RPE1 cells both facilitate cell proliferation suggesting that STAU2 expression influences pathway(s) linked to cell cycle controls. Such effects are not observed in the CRISPR STAU2-KO cancer HCT116 cells nor in the STAU2-RNAi-depleted HeLa cells. Interestingly, a physiological decrease in the steady-state level of STAU2 is controlled by caspases. This effect of peptidases is counterbalanced by the activity of the CHK1 pathway suggesting that STAU2 partial degradation/stabilization fines tune cell cycle progression in unstressed cells. A large-scale proteomic analysis using STAU2/biotinylase fusion protein identifies known STAU2 interactors involved in RNA translation, localization, splicing, or decay confirming the role of STAU2 in the posttranscriptional regulation of gene expression. In addition, several proteins found in the nucleolus, including proteins of the ribosome biogenesis pathway and of the DNA damage response, are found in close proximity to STAU2. Strikingly, many of these proteins are linked to the kinase CHK1 pathway, reinforcing the link between STAU2 functions and the CHK1 pathway. Indeed, inhibition of the CHK1 pathway for 4 h dissociates STAU2 from proteins involved in translation and RNA metabolism.ConclusionsThese results indicate that STAU2 is involved in pathway(s) that control(s) cell proliferation, likely via mechanisms of posttranscriptional regulation, ribonucleoprotein complex assembly, genome integrity and/or checkpoint controls. The mechanism by which STAU2 regulates cell growth likely involves caspases and the kinase CHK1 pathway.


2021 ◽  
Author(s):  
Kerry Silva McPherson ◽  
Dmitry Korzhnev

Cellular DNA damage response (DDR) is an extensive signaling network that orchestrates DNA damage recognition, repair and avoidance, cell cycle progression and cell death. DDR alternation is a hallmark of...


2010 ◽  
Vol 29 (18) ◽  
pp. 3130-3139 ◽  
Author(s):  
Sophie E Polo ◽  
Abderrahmane Kaidi ◽  
Linda Baskcomb ◽  
Yaron Galanty ◽  
Stephen P Jackson

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Jing Song ◽  
Ping Hong ◽  
Chengeng Liu ◽  
Yueqi Zhang ◽  
Jinling Wang ◽  
...  

Cell Cycle ◽  
2013 ◽  
Vol 13 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Marietta Y.W.T. Lee ◽  
Sufang Zhang ◽  
Szu Hua Lin ◽  
Xiaoxiao Wang ◽  
Zbigniew Darzynkiewicz ◽  
...  

2009 ◽  
Vol 187 (6) ◽  
pp. 773-780 ◽  
Author(s):  
Antonio Cerqueira ◽  
David Santamaría ◽  
Bárbara Martínez-Pastor ◽  
Miriam Cuadrado ◽  
Oscar Fernández-Capetillo ◽  
...  

In response to DNA damage, cells activate a phosphorylation-based signaling cascade known as the DNA damage response (DDR). One of the main outcomes of DDR activation is inhibition of cyclin-dependent kinase (Cdk) activity to restrain cell cycle progression until lesions are healed. Recent studies have revealed a reverse connection by which Cdk activity modulates processing of DNA break ends and DDR activation. However, the specific contribution of individual Cdks to this process remains poorly understood. To address this issue, we have examined the DDR in murine cells carrying a defined set of Cdks. Our results reveal that genome maintenance programs of postreplicative cells, including DDR, are regulated by the overall level of Cdk activity and not by specific Cdks.


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