scholarly journals Rescue of DNA damage after constricted migration reveals a mechano-regulated threshold for cell cycle

2019 ◽  
Vol 218 (8) ◽  
pp. 2545-2563 ◽  
Author(s):  
Yuntao Xia ◽  
Charlotte R. Pfeifer ◽  
Kuangzheng Zhu ◽  
Jerome Irianto ◽  
Dazhen Liu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Damage Threshold ◽  
Chromatin Binding ◽  
Lamin B ◽  
Cell Cycle Block ◽  
Break Formation ◽  
Damage Marker ◽  
Partial Effects ◽  
Nuclear Rupture

Migration through 3D constrictions can cause nuclear rupture and mislocalization of nuclear proteins, but damage to DNA remains uncertain, as does any effect on cell cycle. Here, myosin II inhibition rescues rupture and partially rescues the DNA damage marker γH2AX, but an apparent block in cell cycle appears unaffected. Co-overexpression of multiple DNA repair factors or antioxidant inhibition of break formation also exert partial effects, independently of rupture. Combined treatments completely rescue cell cycle suppression by DNA damage, revealing a sigmoidal dependence of cell cycle on excess DNA damage. Migration through custom-etched pores yields the same damage threshold, with ∼4-µm pores causing intermediate levels of both damage and cell cycle suppression. High curvature imposed rapidly by pores or probes or else by small micronuclei consistently associates nuclear rupture with dilution of stiff lamin-B filaments, loss of repair factors, and entry from cytoplasm of chromatin-binding cGAS (cyclic GMP-AMP synthase). The cell cycle block caused by constricted migration is nonetheless reversible, with a potential for DNA misrepair and genome variation.

scholarly journals Rescue of DNA damage in cells after constricted migration reveals bimodal mechano-regulation of cell cycle

2018 ◽  
Author(s):  
Yuntao Xia ◽  
Charlotte R Pfeifer ◽  
Kuangzheng Zhu ◽  
Jerome Irianto ◽  
Dazhen Liu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Genomic Variation ◽  
Chromatin Binding ◽  
Cell Cycle Delay ◽  
Repair Factor ◽  
Regulation Of Cell Cycle ◽  
Break Formation ◽  
Damage Marker ◽  
Partial Effects

Migration through constrictions can clearly rupture nuclei and mis-localize nuclear proteins but damage to DNA remains uncertain as does any effect on cell cycle. Here, myosin-II inhibition rescues rupture and partially rescues the DNA damage marker γH2AX, but an apparent delay in cell cycle is unaffected. Co-overexpression of multiple DNA repair factors and antioxidant inhibition of break formation also have partial effects, independent of rupture. Complete rescue of both DNA damage and cell cycle delay by myosin inhibition plus antioxidant reveals a bimodal dependence of cell cycle on DNA damage. Migration through custom-etched pores yields the same bimodal, with ~4-um pores causing intermediate levels of damage and cell cycle delay. Micronuclei (generated in faulty division) of the smallest diameter appear similar to ruptured nuclei, with high DNA damage and entry of chromatin-binding cGAS (cyclic-GMP-AMP-synthase) from cytoplasm but low repair factor levels. Increased genomic variation after constricted migration is quantified in expanding clones and is consistent with (mis)repair of excess DNA damage and subsequent proliferation.

DNA damage-induced [Zn2+]i transients: correlation with cell cycle arrest and apoptosis in lymphoma cells

2002 ◽  
Vol 283 (2) ◽  
pp. C609-C622 ◽  
Author(s):  
Paul J. Smith ◽  
Marie Wiltshire ◽  
Sharon Davies ◽  
Suet-Feung Chin ◽  
Anthony K. Campbell ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Stress Responses ◽  
Damage Threshold ◽  
Lymphoma Cells ◽  
Cycle Arrest ◽  
Competent Cells ◽  
Drug Doses ◽  
Induced Apoptosis

Reactive changes in free intracellular zinc cation concentration ([Zn2+]i) were monitored, using the fluorescent probe Zinquin, in human lymphoma cells exposed to the DNA-damaging agent VP-16. Two-photon excitation microscopy showed that Zinquin-Zn2+ forms complexes in cytoplasmic vesicles. [Zn2+]iincreased in both p53wt (wild type) and p53mut(mutant) cells after exposure to low drug doses. In p53mutcells noncompetent for DNA damage-induced apoptosis, elevated [Zn2+]i was maintained at higher drug doses, unlike competent p53wt cells that showed a collapse of the transient before apoptosis. In p53wt cells, the [Zn2+]i rise paralleled an increase in p53 and bax-to-bcl-2 ratio but preceded an increase in p21WAF1, active cell cycle arrest in G2, or nuclear fragmentation. Reducing [Zn2+]i, using N, N, N′, N′-tetrakis(2-pyridylmethyl)ethylenediamine, caused rapid apoptosis in both p53wt and p53mut cells, although cotreatment with VP-16 exacerbated apoptosis only in p53wt cells. This may reflect changed thresholds for proapoptotic caspase-3 activation in competent cells. We conclude that the DNA damage-induced transient is p53-independent up to a damage threshold, beyond which competent cells reduce [Zn2+]i before apoptosis. Early stress responses in p53wt cells take place in an environment of enhanced Zn2+ availability.

scholarly journals TIF1 Proteins in Genome Stability and Cancer

Cancers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2094 ◽  
Author(s):  
Roisin M. McAvera ◽  
Lisa J. Crawford
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Genome Stability ◽  
Cell Cycle Progression ◽  
Binding Proteins ◽  
Chromatin Binding ◽  
Cycle Progression ◽  
E3 Ligases ◽  
Cancer Types ◽  
Cycle Regulation

Genomic instability is a hallmark of cancer cells which results in excessive DNA damage. To counteract this, cells have evolved a tightly regulated DNA damage response (DDR) to rapidly sense DNA damage and promote its repair whilst halting cell cycle progression. The DDR functions predominantly within the context of chromatin and requires the action of chromatin-binding proteins to coordinate the appropriate response. TRIM24, TRIM28, TRIM33 and TRIM66 make up the transcriptional intermediary factor 1 (TIF1) family of chromatin-binding proteins, a subfamily of the large tripartite motif (TRIM) family of E3 ligases. All four TIF1 proteins are aberrantly expressed across numerous cancer types, and increasing evidence suggests that TIF1 family members can function to maintain genome stability by mediating chromatin-based responses to DNA damage. This review provides an overview of the TIF1 family in cancer, focusing on their roles in DNA repair, chromatin regulation and cell cycle regulation.

scholarly journals Mechanosensing by the Lamina Protects against Nuclear Rupture, DNA Damage, and Cell-Cycle Arrest

2019 ◽  
Vol 49 (6) ◽  
pp. 920-935.e5 ◽  
Author(s):  
Sangkyun Cho ◽  
Manasvita Vashisth ◽  
Amal Abbas ◽  
Stephanie Majkut ◽  
Kenneth Vogel ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Cycle Arrest ◽  
Nuclear Rupture

scholarly journals Mechanosensing by the lamina protects against nuclear rupture, DNA damage, and cell cycle arrest

2019 ◽  
Author(s):  
Sangkyun Cho ◽  
Manasvita Vashisth ◽  
Amal Abbas ◽  
Stephanie Majkut ◽  
Kenneth Vogel ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Cell Types ◽  
Genome Integrity ◽  
Lamin A ◽  
Cycle Arrest ◽  
Nonmuscle Cell ◽  
Repair Factor ◽  
Nuclear Rupture

SummaryWhether cell forces or extracellular matrix (ECM) can impact genome integrity is largely unclear. Here, acute perturbations (~1hr) to actomyosin stress or ECM elasticity cause rapid and reversible changes in lamin-A, DNA damage, and cell cycle. Embryonic hearts, differentiated iPS-cells, and various nonmuscle cell types all show that actomyosin-driven nuclear rupture causes cytoplasmic mis-localization of DNA repair factors and excess DNA damage. Binucleation and micronuclei increase as telomeres shorten, which all favor cell cycle arrest. Deficiencies in lamin-A and repair factors exacerbate these effects, but lamin-A-associated defects are rescued by repair factor overexpression and by contractility modulators in clinical trials. Contractile cells on stiff ECM normally exhibit low phosphorylation and slow degradation of lamin-A by matrix-metalloprotease-2 (MMP2), and inhibition of this lamin-A turnover and also actomyosin contractility is seen to minimize DNA damage. Lamin-A is thus stress-stabilized to mechano-protect the genome.

scholarly journals The Chromatin-binding Protein Spn1 contributes to Genome Instability in Saccharomyces cerevisiae

2018 ◽  
Author(s):  
Alison K. Thurston ◽  
Catherine A. Radebaugh ◽  
Adam R. Almeida ◽  
Juan Lucas Argueso ◽  
Laurie A. Stargell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Damage ◽  
Genome Stability ◽  
Damage Tolerance ◽  
Genome Instability ◽  
Chromatin Binding ◽  
Dna Damage Tolerance ◽  
Template Switch

AbstractCells expend a large amount of energy to maintain their DNA sequence. DNA repair pathways, cell cycle checkpoint activation, proofreading polymerases, and chromatin structure are ways in which the cell minimizes changes to the genome. During replication, the DNA damage tolerance pathway allows the replication forks to bypass damage on the template strand. This avoids prolonged replication fork stalling, which can contribute to genome instability. The DNA damage tolerance pathway includes two sub-pathways: translesion synthesis and template switch. Post-translational modification of PCNA and the histone tails, cell cycle phase, and local DNA structure have all been shown to influence sub-pathway choice. Chromatin architecture contributes to maintaining genome stability by providing physical protection of the DNA and by regulating DNA processing pathways. As such, chromatin-binding factors have been implicated in maintaining genome stability. Using Saccharomyces cerevisiae, we examined the role of Spn1, a chromatin binding and transcription elongation factor, in DNA damage tolerance. Expression of a mutant allele of SPN1 results in increased resistance to the DNA damaging agent methyl methanesulfonate, lower spontaneous and damage-induced mutation rates, along with increased chronological lifespan. We attribute these effects to an increased usage of the template switch branch of the DNA damage tolerance pathway in the spn1 strain. This provides evidence for a role of wild type Spn1 in promoting genome instability, as well as having ties to overcoming replication stress and contributing to chronological aging.

scholarly journals Response of the Green Alga Chlamydomonas reinhardtii to the DNA Damaging Agent Zeocin

Cells ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 735 ◽  
Author(s):  
Mária Čížková ◽  
Monika Slavková ◽  
Milada Vítová ◽  
Vilém Zachleder ◽  
Kateřina Bišová
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Chlamydomonas Reinhardtii ◽  
Green Alga ◽  
Cell Cycle Progression ◽  
Kinase Activity ◽  
Cyclin Dependent Kinase ◽  
Cycle Progression ◽  
Mitotic Cyclin ◽  
Cell Cycle Block

DNA damage is a ubiquitous threat endangering DNA integrity in all living organisms. Responses to DNA damage include, among others, induction of DNA repair and blocking of cell cycle progression in order to prevent transmission of damaged DNA to daughter cells. Here, we tested the effect of the antibiotic zeocin, inducing double stranded DNA breaks, on the cell cycle of synchronized cultures of the green alga Chlamydomonas reinhardtii. After zeocin application, DNA replication partially occurred but nuclear and cellular divisions were completely blocked. Application of zeocin combined with caffeine, known to alleviate DNA checkpoints, decreased cell viability significantly. This was probably caused by a partial overcoming of the cell cycle progression block in such cells, leading to aberrant cell divisions. The cell cycle block was accompanied by high steady state levels of mitotic cyclin-dependent kinase activity. The data indicate that DNA damage response in C. reinhardtii is connected to the cell cycle block, accompanied by increased and stabilized mitotic cyclin-dependent kinase activity.

scholarly journals UHRF1 depletion causes a G2/M arrest, activation of DNA damage response and apoptosis

2011 ◽  
Vol 435 (1) ◽  
pp. 175-185 ◽  
Author(s):  
Amy L. Tien ◽  
Sucharita Senbanerjee ◽  
Atul Kulkarni ◽  
Raksha Mudbhary ◽  
Bernadette Goudreau ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Epigenetic Regulation ◽  
Cell Cycle Progression ◽  
Ring Finger ◽  
Caspase 8 ◽  
Histone H2ax ◽  
Damage Response ◽  
Cell Cycle Block

UHRF1 [ubiquitin-like protein, containing PHD (plant homeodomain) and RING finger domains 1] is required for cell cycle progression and epigenetic regulation. In the present study, we show that depleting cancer cells of UHRF1 causes activation of the DNA damage response pathway, cell cycle arrest in G2/M-phase and apoptosis dependent on caspase 8. The DNA damage response in cells depleted of UHRF1 is illustrated by: phosphorylation of histone H2AX on Ser139, phosphorylation of CHK (checkpoint kinase) 2 on Thr68, phosphorylation of CDC25 (cell division control 25) on Ser216 and phosphorylation of CDK1 (cyclin-dependent kinase 1) on Tyr15. Moreover, we find that UHRF1 accumulates at sites of DNA damage suggesting that the cell cycle block in UHRF1-depleted cells is due to an important role in damage repair. The consequence of UHRF1 depletion is apoptosis; cells undergo activation of caspases 8 and 3, and depletion of caspase 8 prevents cell death induced by UHRF1 knockdown. Interestingly, the cell cycle block and apoptosis occurs in p53-containing and -deficient cells. From the present study we conclude that UHRF1 links epigenetic regulation with DNA replication.

scholarly journals Nuclear rupture at sites of high curvature compromises retention of DNA repair factors

2018 ◽  
Vol 217 (11) ◽  
pp. 3796-3808 ◽  
Author(s):  
Yuntao Xia ◽  
Irena L. Ivanovska ◽  
Kuangzheng Zhu ◽  
Lucas Smith ◽  
Jerome Irianto ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Dna Damage ◽  
Dna Repair ◽  
Opposite Effect ◽  
Cell Attachment ◽  
Collagen Fibers ◽  
Lamin A ◽  
Soft Matrix ◽  
Damage Marker ◽  
Nuclear Rupture

The nucleus is physically linked to the cytoskeleton, adhesions, and extracellular matrix—all of which sustain forces, but their relationships to DNA damage are obscure. We show that nuclear rupture with cytoplasmic mislocalization of multiple DNA repair factors correlates with high nuclear curvature imposed by an external probe or by cell attachment to either aligned collagen fibers or stiff matrix. Mislocalization is greatly enhanced by lamin A depletion, requires hours for nuclear reentry, and correlates with an increase in pan-nucleoplasmic foci of the DNA damage marker γH2AX. Excess DNA damage is rescued in ruptured nuclei by cooverexpression of multiple DNA repair factors as well as by soft matrix or inhibition of actomyosin tension. Increased contractility has the opposite effect, and stiff tumors with low lamin A indeed exhibit increased nuclear curvature, more frequent nuclear rupture, and excess DNA damage. Additional stresses likely play a role, but the data suggest high curvature promotes nuclear rupture, which compromises retention of DNA repair factors and favors sustained damage.

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