Faculty Opinions recommendation of Overlapping roles of the spindle assembly and DNA damage checkpoints in the cell-cycle response to altered chromosomes in Saccharomyces cerevisiae.

2002 ◽  
Author(s):  
Susan Forsburg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Damage ◽  
Spindle Assembly ◽  
Dna Damage Checkpoints

SPK1 is an essential S-phase-specific gene of Saccharomyces cerevisiae that encodes a nuclear serine/threonine/tyrosine kinase

1993 ◽  
Vol 13 (9) ◽  
pp. 5829-5842
Author(s):  
P Zheng ◽  
D S Fay ◽  
J Burton ◽  
H Xiao ◽  
J L Pinkham ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Damage ◽  
Dna Synthesis ◽  
Genomic Library ◽  
Excision Repair ◽  
Low Frequency ◽  
S Phase ◽  
Upstream Region ◽  
Specific Gene

SPK1 was originally discovered in an immunoscreen for tyrosine-protein kinases in Saccharomyces cerevisiae. We have used biochemical and genetic techniques to investigate the function of this gene and its encoded protein. Hybridization of an SPK1 probe to an ordered genomic library showed that SPK1 is adjacent to PEP4 (chromosome XVI L). Sporulation of spk1/+ heterozygotes gave rise to spk1 spores that grew into microcolonies but could not be further propagated. These colonies were greatly enriched for budded cells, especially those with large buds. Similarly, eviction of CEN plasmids bearing SPK1 from cells with a chromosomal SPK1 disruption yielded viable cells with only low frequency. Spk1 protein was identified by immunoprecipitation and immunoblotting. It was associated with protein-Ser, Thr, and Tyr kinase activity in immune complex kinase assays. Spk1 was localized to the nucleus by immunofluorescence. The nucleotide sequence of the SPK1 5' noncoding region revealed that SPK1 contains two MluI cell cycle box elements. These elements confer S-phase-specific transcription to many genes involved in DNA synthesis. Northern (RNA) blotting of synchronized cells verified that the SPK1 transcript is coregulated with other MluI box-regulated genes. The SPK1 upstream region also includes a domain highly homologous to sequences involved in induction of RAD2 and other excision repair genes by agents that induce DNA damage. spk1 strains were hypersensitive to UV irradiation. Taken together, these findings indicate that SPK1 is a dual-specificity (Ser/Thr and Tyr) protein kinase that is essential for viability. The cell cycle-dependent transcription, presence of DNA damage-related sequences, requirement for UV resistance, and nuclear localization of Spk1 all link this gene to a crucial S-phase-specific role, probably as a positive regulator of DNA synthesis.

scholarly journals MEC3, MEC1, and DDC2Are Essential Components of a Telomere Checkpoint Pathway Required for Cell Cycle Arrest during Senescence in Saccharomyces cerevisiae

2002 ◽  
Vol 13 (8) ◽  
pp. 2626-2638 ◽  
Author(s):  
Shinichiro Enomoto ◽  
Lynn Glowczewski ◽  
Judith Berman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Damage ◽  
Telomerase Activity ◽  
Cellular Level ◽  
Dna Damage Checkpoint ◽  
Average Growth ◽  
Progressive Decline ◽  
Checkpoint Response ◽  
Essential Components

When telomerase is absent and/or telomeres become critically short, cells undergo a progressive decline in viability termed senescence. The telomere checkpoint model predicts that cells will respond to a damaged or critically short telomere by transiently arresting and activating repair of the telomere. We examined the senescence of telomerase-deficient Saccharomyces cerevisiae at the cellular level to ask if the loss of telomerase activity triggers a checkpoint response. As telomerase-deficient mutants were serially subcultured, cells exhibited a progressive decline in average growth rate and an increase in the number of cells delayed in the G2/M stage of the cell cycle. MEC3, MEC1, andDDC2, genes important for the DNA damage checkpoint response, were required for the cell cycle delay in telomerase-deficient cells. In contrast, TEL1,RAD9, and RAD53, genes also required for the DNA damage checkpoint response, were not required for the G2/M delay in telomerase-deficient cells. We propose that the telomere checkpoint is distinct from the DNA damage checkpoint and requires a specific set of gene products to delay the cell cycle and presumably to activate telomerase and/or other telomere repair activities.

Role of the Saccharomyces cerevisiae Rad9 protein in sensing and responding to DNA damage

2003 ◽  
Vol 31 (1) ◽  
pp. 242-246 ◽  
Author(s):  
G.W.-L. Toh ◽  
N.F. Lowndes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Damage ◽  
Cellular Responses ◽  
Eukaryotic Cells ◽  
Genome Damage ◽  
Dna Damage Checkpoints ◽  
Repair Mechanisms ◽  
Sense And Respond ◽  
Insight Into

Eukaryotic cells have evolved surveillance mechanisms, known as DNA-damage checkpoints, that sense and respond to genome damage. DNA-damage checkpoint pathways ensure co-ordinated cellular responses to DNA damage, including cell cycle delays and activation of repair mechanisms. RAD9, from Saccharomyces cerevisiae, was the first damage checkpoint gene to be identified, although its biochemical function remained unknown until recently. This review examines briefly work that provides significant insight into how Rad9 activates the checkpoint signalling kinase Rad53.

scholarly journals Telomerase subunit Est2 marks internal sites that are prone to accumulate DNA damage

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Satyaprakash Pandey ◽  
Mona Hajikazemi ◽  
Theresa Zacheja ◽  
Stephanie Schalbetter ◽  
Jonathan Baxter ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Damage ◽  
Binding Sites ◽  
Genome Stability ◽  
Main Function ◽  
Adverse Conditions ◽  
G2 Phase ◽  
Telomerase Regulation ◽  
Novel Model

Abstract Background The main function of telomerase is at the telomeres but under adverse conditions telomerase can bind to internal regions causing deleterious effects as observed in cancer cells. Results By mapping the global occupancy of the catalytic subunit of telomerase (Est2) in the budding yeast Saccharomyces cerevisiae, we reveal that it binds to multiple guanine-rich genomic loci, which we termed “non-telomeric binding sites” (NTBS). We characterize Est2 binding to NTBS. Contrary to telomeres, Est2 binds to NTBS in G1 and G2 phase independently of Est1 and Est3. The absence of Est1 and Est3 renders telomerase inactive at NTBS. However, upon global DNA damage, Est1 and Est3 join Est2 at NTBS and telomere addition can be observed indicating that Est2 occupancy marks NTBS regions as particular risks for genome stability. Conclusions Our results provide a novel model of telomerase regulation in the cell cycle using internal regions as “parking spots” of Est2 but marking them as hotspots for telomere addition.

scholarly journals DNA damage checkpoint dynamics drive cell cycle phase transitions

2017 ◽  
Author(s):  
Hui Xiao Chao ◽  
Cere E. Poovey ◽  
Ashley A. Privette ◽  
Gavin D. Grant ◽  
Hui Yan Chao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Phase Transitions ◽  
Cell Cycle Progression ◽  
S Phase ◽  
Cell Cycle Phase ◽  
Cycle Phase ◽  
Dna Damage Checkpoint ◽  
Cycle Progression ◽  
Dna Damage Checkpoints

ABSTRACTDNA damage checkpoints are cellular mechanisms that protect the integrity of the genome during cell cycle progression. In response to genotoxic stress, these checkpoints halt cell cycle progression until the damage is repaired, allowing cells enough time to recover from damage before resuming normal proliferation. Here, we investigate the temporal dynamics of DNA damage checkpoints in individual proliferating cells by observing cell cycle phase transitions following acute DNA damage. We find that in gap phases (G1 and G2), DNA damage triggers an abrupt halt to cell cycle progression in which the duration of arrest correlates with the severity of damage. However, cells that have already progressed beyond a proposed “commitment point” within a given cell cycle phase readily transition to the next phase, revealing a relaxation of checkpoint stringency during later stages of certain cell cycle phases. In contrast to G1 and G2, cell cycle progression in S phase is significantly less sensitive to DNA damage. Instead of exhibiting a complete halt, we find that increasing DNA damage doses leads to decreased rates of S-phase progression followed by arrest in the subsequent G2. Moreover, these phase-specific differences in DNA damage checkpoint dynamics are associated with corresponding differences in the proportions of irreversibly arrested cells. Thus, the precise timing of DNA damage determines the sensitivity, rate of cell cycle progression, and functional outcomes for damaged cells. These findings should inform our understanding of cell fate decisions after treatment with common cancer therapeutics such as genotoxins or spindle poisons, which often target cells in a specific cell cycle phase.

scholarly journals Caffeine Stabilises Fission Yeast Wee1 in a Rad24-Dependent Manner but Attenuates Its Expression in Response to DNA Damage

2020 ◽  
Vol 8 (10) ◽  
pp. 1512
Author(s):  
John P. Alao ◽  
Johanna Johansson-Sjölander ◽  
Charalampos Rallis ◽  
Per Sunnerhagen
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Stress Response ◽  
Environmental Stress ◽  
Cell Cycle Progression ◽  
Dependent Manner ◽  
Environmental Stress Response ◽  
Cycle Progression ◽  
Dna Damage Checkpoints ◽  
Wee1 Kinase

The widely consumed neuroactive compound caffeine has generated much interest due to its ability to override the DNA damage and replication checkpoints. Previously Rad3 and its homologues was thought to be the target of caffeine’s inhibitory activity. Later findings indicate that the Target of Rapamycin Complex 1 (TORC1) is the preferred target of caffeine. Effective Cdc2 inhibition requires both the activation of the Wee1 kinase and inhibition of the Cdc25 phosphatase. The TORC1, DNA damage, and environmental stress response pathways all converge on Cdc25 and Wee1. We previously demonstrated that caffeine overrides DNA damage checkpoints by modulating Cdc25 stability. The effect of caffeine on cell cycle progression resembles that of TORC1 inhibition. Furthermore, caffeine activates the Sty1 regulated environmental stress response. Caffeine may thus modulate multiple signalling pathways that regulate Cdc25 and Wee1 levels, localisation and activity. Here we show that the activity of caffeine stabilises both Cdc25 and Wee1. The stabilising effect of caffeine and genotoxic agents on Wee1 was dependent on the Rad24 chaperone. Interestingly, caffeine inhibited the accumulation of Wee1 in response to DNA damage. Caffeine may modulate cell cycle progression through increased Cdc25 activity and Wee1 repression following DNA damage via TORC1 inhibition, as TORC1 inhibition increased DNA damage sensitivity.

Cell Cycle: DNA Damage Checkpoints

2021 ◽  
Author(s):  
Matthew D. Weitzman ◽  
Jean Y.J. Wang ◽  
Vikash Verma
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Damage Checkpoints

Characterization of RAD9 of Saccharomyces cerevisiae and evidence that its function acts posttranslationally in cell cycle arrest after DNA damage

1990 ◽  
Vol 10 (12) ◽  
pp. 6554-6564
Author(s):  
T A Weinert ◽  
L H Hartwell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Dna Sequence ◽  
Negative Regulator ◽  
Yeast Cells ◽  
Protein Synthesis Inhibitor ◽  
Cycle Arrest ◽  
Delta Cells

In eucaryotic cells, incompletely replicated or damaged chromosomes induce cell cycle arrest in G2 before mitosis, and in the yeast Saccharomyces cerevisiae the RAD9 gene is essential for the cell cycle arrest (T.A. Weinert and L. H. Hartwell, Science 241:317-322, 1988). In this report, we extend the analysis of RAD9-dependent cell cycle control. We found that both induction of RAD9-dependent arrest in G2 and recovery from arrest could occur in the presence of the protein synthesis inhibitor cycloheximide, showing that the mechanism of RAD9-dependent control involves a posttranslational mechanism(s). We have isolated and determined the DNA sequence of the RAD9 gene, confirming the DNA sequence reported previously (R. H. Schiestl, P. Reynolds, S. Prakash, and L. Prakash, Mol. Cell. Biol. 9:1882-1886, 1989). The predicted protein sequence for the Rad9 protein bears no similarity to sequences of known proteins. We also found that synthesis of the RAD9 transcript in the cell cycle was constitutive and not induced by X-irradiation. We constructed yeast cells containing a complete deletion of the RAD9 gene; the rad9 null mutants were viable, sensitive to X- and UV irradiation, and defective for cell cycle arrest after DNA damage. Although Rad+ and rad9 delta cells had similar growth rates and cell cycle kinetics in unirradiated cells, the spontaneous rate of chromosome loss (in unirradiated cells) was elevated 7- to 21-fold in rad9 delta cells. These studies show that in the presence of induced or endogenous DNA damage, RAD9 is a negative regulator that inhibits progression from G2 in order to preserve cell viability and to maintain the fidelity of chromosome transmission.

Sign in / Sign up

Export Citation Format

Share Document