Pds1p, an inhibitor of anaphase in budding yeast, plays a critical role in the APC and checkpoint pathway(s).

We report the isolation and characterization of pds1 mutants in Saccharomyces cerevisiae. The initial pds1-1 allele was identified by its inviability after transient exposure to microtubule inhibitors and its precocious dissociation of sister chromatids in the presence of these microtubule inhibitors. These findings suggest that pds1 mutants might be defective in anaphase arrest that normally is imposed by a spindle-damage checkpoint. To further examine a role for Pds1p in anaphase arrest, we compared the cell cycle arrest of pds1 mutants and PDS1 cells after: (a) the inactivation of Cdc16p or Cdc23p, two proteins that are required for the degradation of mitotic cyclins and are putative components of the yeast anaphase promoting complex (APC); (b) the inactivation of Cdc20p, another protein implicated in the degradation of mitotic cyclins; and (c) the inactivation of Cdc13 protein or gamma irradiation, two circumstances that induce a DNA-damage checkpoint. Under all these conditions, anaphase is inhibited in PDS1 cells but not in pds1 mutants. From these results we suggest that Pds1 protein is an anaphase inhibitor in PDS1 cells but not in pds1 mutants. From these results we suggest that Pds1 protein is an anaphase inhibitor that plays a critical role in the control of anaphase by both APC and checkpoints. We also show that pds1 mutants exit mitosis and initiate new rounds of cell division after gamma irradiation and Cdc13p inactivation but no after nocodazole-treatment or inactivation of Cdc16p, Cdc20p or Cdc23p function. Therefore, in the DNA-damage checkpoint, Pds1p is required for the inhibition of cytokinesis and DNA replication as well as anaphase. The role of Pds1 protein in anaphase inhibition and general cell cycle regulation is discussed.

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The G(2) DNA damage checkpoint targets both Wee1 and Cdc25

Journal of Cell Science ◽

10.1242/jcs.113.10.1727 ◽

2000 ◽

Vol 113 (10) ◽

pp. 1727-1736 ◽

Cited By ~ 13

Author(s):

J.M. Raleigh ◽

M.J. O'Connell

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Cell Cycle Progression ◽

Dna Damage Checkpoint ◽

Checkpoint Control ◽

Down Regulation ◽

Cycle Progression ◽

Cycle Arrest ◽

Checkpoint Pathway

The onset of mitosis is controlled by the cyclin dependent kinase Cdc2p. Cdc2p activity is controlled through the balance of phosphorylation and dephosphorylation of tyrosine-15 (Y15) by the Wee1p kinase and Cdc25p phosphatase. In the fission yeast Schizosaccharomyces pombe, detection of DNA damage in G(2) activates a checkpoint that prevents entry into mitosis through the maintenance of Y15 phosphorylation of Cdc2p, thus ensuring DNA repair precedes chromosome segregation. The protein kinase Chk1p is the endpoint of this checkpoint pathway. We have previously reported that overexpression of Chk1p causes a wee1(+)-dependent G(2) arrest, and this or irradiation leads to hyperphosphorylation of Wee1p. Moreover, Chk1p directly phosphorylates Wee1p in vitro. These data suggested that Wee1p is a key target of Chk1p action in checkpoint control. However, cells lacking wee1(+) are checkpoint proficient and sustained Chk1p overexpression arrests cell cycle progression independently of Wee1p. Therefore, up-regulation of Wee1p alone cannot enforce a checkpoint arrest. Chk1p can also phosphorylate Cdc25p in vitro. These phosphorylation events are thought to promote the interaction with 14–3-3 proteins the cytoplasmic retention of the 14–3-3/Cdc25p complexes. However, we show here that the G(2) DNA damage checkpoint is intact in cells that regulate mitotic entry independently of Cdc25p. Further, these cells are still sensitive to Chk1p-mediated arrest, and so down-regulation of Cdc25p is also insufficient to regulate checkpoint arrest. Conversely, inactivation of both wee1(+) and cdc25(+)abolishes checkpoint control. We also show that activation of the G(2) DNA damage checkpoint induces a transient increase in Wee1p levels. We conclude that the G(2) DNA damage checkpoint simultaneously signals via both up-regulation of Wee1p and down-regulation of Cdc25p, thus providing a double-lock mechanism to ensure cell cycle arrest and genomic stability.

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Babam2 Regulates Cell Cycle Progression and Pluripotency in Mouse Embryonic Stem Cells as Revealed by Induced DNA Damage

Biomedicines ◽

10.3390/biomedicines8100397 ◽

2020 ◽

Vol 8 (10) ◽

pp. 397

Author(s):

Cheuk Yiu Tenny Chung ◽

Paulisally Hau Yi Lo ◽

Kenneth Ka Ho Lee

Keyword(s):

Cell Cycle ◽

Stem Cells ◽

Dna Damage ◽

Gamma Irradiation ◽

Cellular Senescence ◽

Cell Cycle Regulation ◽

Cell Cycle Progression ◽

Embryonic Stem ◽

Cycle Progression ◽

Cycle Regulation

BRISC and BRCA1-A complex member 2 (Babam2) plays an essential role in promoting cell cycle progression and preventing cellular senescence. Babam2-deficient fibroblasts show proliferation defect and premature senescence compared with their wild-type (WT) counterpart. Pluripotent mouse embryonic stem cells (mESCs) are known to have unlimited cell proliferation and self-renewal capability without entering cellular senescence. Therefore, studying the role of Babam2 in ESCs would enable us to understand the mechanism of Babam2 in cellular aging, cell cycle regulation, and pluripotency in ESCs. For this study, we generated Babam2 knockout (Babam2−/−) mESCs to investigate the function of Babam2 in mESCs. We demonstrated that the loss of Babam2 in mESCs leads to abnormal G1 phase retention in response to DNA damage induced by gamma irradiation or doxorubicin treatments. Key cell cycle regulators, CDC25A and CDK2, were found to be degraded in Babam2−/− mESCs following gamma irradiation. In addition, Babam2−/− mESCs expressed p53 strongly and significantly longer than in control mESCs, where p53 inhibited Nanog expression and G1/S cell cycle progression. The combined effects significantly reduced developmental pluripotency in Babam2−/− mESCs. In summary, Babam2 maintains cell cycle regulation and pluripotency in mESCs in response to induced DNA damage.

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Critical Role for Mouse Hus1 in an S-Phase DNA Damage Cell Cycle Checkpoint

Molecular and Cellular Biology ◽

10.1128/mcb.23.3.791-803.2003 ◽

2003 ◽

Vol 23 (3) ◽

pp. 791-803 ◽

Cited By ~ 50

Author(s):

Robert S. Weiss ◽

Philip Leder ◽

Cyrus Vaziri

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Dna Synthesis ◽

Critical Role ◽

S Phase ◽

Cell Cycle Checkpoint ◽

Dna Damage Checkpoint ◽

Null Mouse ◽

Cycle Checkpoint ◽

S Phase Checkpoint

ABSTRACT Mouse Hus1 encodes an evolutionarily conserved DNA damage response protein. In this study we examined how targeted deletion of Hus1 affects cell cycle checkpoint responses to genotoxic stress. Unlike hus1− fission yeast (Schizosaccharomyces pombe) cells, which are defective for the G2/M DNA damage checkpoint, Hus1-null mouse cells did not inappropriately enter mitosis following genotoxin treatment. However, Hus1-deficient cells displayed a striking S-phase DNA damage checkpoint defect. Whereas wild-type cells transiently repressed DNA replication in response to benzo(a)pyrene dihydrodiol epoxide (BPDE), a genotoxin that causes bulky DNA adducts, Hus1-null cells maintained relatively high levels of DNA synthesis following treatment with this agent. However, when treated with DNA strand break-inducing agents such as ionizing radiation (IR), Hus1-deficient cells showed intact S-phase checkpoint responses. Conversely, checkpoint-mediated inhibition of DNA synthesis in response to BPDE did not require NBS1, a component of the IR-responsive S-phase checkpoint pathway. Taken together, these results demonstrate that Hus1 is required specifically for one of two separable mammalian checkpoint pathways that respond to distinct forms of genome damage during S phase.

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Down-regulation of nuclear protein ICBP90 by p53/p21Cip1/WAF1-dependent DNA-damage checkpoint signals contributes to cell cycle arrest at G1/S transition

Genes to Cells ◽

10.1111/j.1356-9597.2004.00710.x ◽

2004 ◽

Vol 9 (2) ◽

pp. 131-142 ◽

Cited By ~ 91

Author(s):

Yoshimi Arima ◽

Toru Hirota ◽

Christian Bronner ◽

Marc Mousli ◽

Toshiyoshi Fujiwara ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Cell Cycle Arrest ◽

Nuclear Protein ◽

Dna Damage Checkpoint ◽

Down Regulation ◽

Cycle Arrest

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The NUCKS1-SKP2-p21/p27 axis controls S phase entry

10.1101/2021.06.29.450420 ◽

2021 ◽

Author(s):

Samuel Hume ◽

Claudia P Grou ◽

Pauline Lascaux ◽

Vincenzo D'Angiolella ◽

Arnaud J Legrand ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Ubiquitin Ligase ◽

Transcriptional Repression ◽

S Phase ◽

Tissue Homeostasis ◽

Cycle Arrest ◽

Checkpoint Pathway ◽

Dna Damage Signalling ◽

Phase Entry

Efficient entry into S phase of the cell cycle is necessary for embryonic development and tissue homeostasis. However, unscheduled S phase entry triggers DNA damage and promotes oncogenesis, underlining the requirement for strict control. Here, we identify the NUCKS1-SKP2-p21/p27 axis as a checkpoint pathway for the G1/S transition. In response to mitogenic stimulation, NUCKS1, a transcription factor, is recruited to chromatin to activate expression of SKP2, the F-box component of the SCFSKP2 ubiquitin ligase, leading to degradation of p21 and p27 and promoting progression into S phase. In contrast, DNA damage induces p53-dependent transcriptional repression of NUCKS1, leading to SKP2 downregulation, p21/p27 upregulation, and cell cycle arrest. We propose that the NUCKS1-SKP2-p21/p27 axis integrates mitogenic and DNA damage signalling to control S phase entry. TCGA data reveal that this mechanism is hijacked in cancer, potentially allowing cancer cells to sustain uncontrolled proliferation.

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Genistein induces G2/M cell cycle arrest and apoptosis of human ovarian cancer cells via activation of DNA damage checkpoint pathways

Cell Biology International ◽

10.1016/j.cellbi.2009.08.011 ◽

2009 ◽

Vol 33 (12) ◽

pp. 1237-1244 ◽

Cited By ~ 78

Author(s):

Gaoliang Ouyang ◽

Luming Yao ◽

Kai Ruan ◽

Gang Song ◽

Yubin Mao ◽

...

Keyword(s):

Cell Cycle ◽

Ovarian Cancer ◽

Dna Damage ◽

Cell Cycle Arrest ◽

Cancer Cells ◽

Ovarian Cancer Cells ◽

Dna Damage Checkpoint ◽

Human Ovarian Cancer ◽

M Cell ◽

Cycle Arrest

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Critical role of SMG7 in activation of the ATR-CHK1 axis in response to genotoxic stress

Scientific Reports ◽

10.1038/s41598-021-86957-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kathleen Ho ◽

Hongwei Luo ◽

Wei Zhu ◽

Yi Tang

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Dna Replication ◽

Cell Cycle Progression ◽

Critical Role ◽

Genotoxic Stress ◽

Dna Damage Checkpoint ◽

Cycle Progression ◽

Essential Step

AbstractCHK1 is a crucial DNA damage checkpoint kinase and its activation, which requires ATR and RAD17, leads to inhibition of DNA replication and cell cycle progression. Recently, we reported that SMG7 stabilizes and activates p53 to induce G1 arrest upon DNA damage; here we show that SMG7 plays a critical role in the activation of the ATR-CHK1 axis. Following genotoxic stress, SMG7-null cells exhibit deficient ATR signaling, indicated by the attenuated phosphorylation of CHK1 and RPA32, and importantly, unhindered DNA replication and fork progression. Through its 14-3-3 domain, SMG7 interacts directly with the Ser635-phosphorylated RAD17 and promotes chromatin retention of the 9-1-1 complex by the RAD17-RFC, an essential step to CHK1 activation. Furthermore, through maintenance of CHK1 activity, SMG7 controls G2-M transition and facilitates orderly cell cycle progression during recovery from replication stress. Taken together, our data reveals SMG7 as an indispensable signaling component in the ATR-CHK1 pathway during genotoxic stress response.

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DNA Damage-Induced Cell Cycle Regulation and Function of Novel Chk2 Phosphoresidues

Molecular and Cellular Biology ◽

10.1128/mcb.00534-06 ◽

2006 ◽

Vol 26 (21) ◽

pp. 7832-7845 ◽

Cited By ~ 33

Author(s):

Giacomo Buscemi ◽

Luigi Carlessi ◽

Laura Zannini ◽

Sofia Lisanti ◽

Enrico Fontanella ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Ataxia Telangiectasia ◽

Dna Double Strand Breaks ◽

Independent Manner ◽

Strand Breaks ◽

Cycle Arrest ◽

And Function ◽

Cycle Regulation

ABSTRACT Chk2 kinase is activated by DNA damage to regulate cell cycle arrest, DNA repair, and apoptosis. Phosphorylation of Chk2 in vivo by ataxia telangiectasia-mutated (ATM) on threonine 68 (T68) initiates a phosphorylation cascade that promotes the full activity of Chk2. We identified three serine residues (S19, S33, and S35) on Chk2 that became phosphorylated in vivo rapidly and exclusively in response to ionizing radiation (IR)-induced DNA double-strand breaks in an ATM- and Nbs1-dependent but ataxia telangiectasia- and Rad3-related-independent manner. Phosphorylation of these residues, restricted to the G1 phase of the cell cycle, was induced by a higher dose of IR (>1 Gy) than that required for phosphorylation of T68 (0.25 Gy) and declined by 45 to 90 min, concomitant with a rise in Chk2 autophosphorylation. Compared to the wild-type form, Chk2 with alanine substitutions at S19, S33, and S35 (Chk2S3A) showed impaired dimerization, defective auto- and trans-phosphorylation activities, and reduced ability to promote degradation of Hdmx, a phosphorylation target of Chk2 and regulator of p53 activity. Besides, Chk2S3A failed to inhibit cell growth and, in response to IR, to arrest G1/S progression. These findings underscore the critical roles of S19, S33, and S35 and argue that these phosphoresidues may serve to fine-tune the ATM-dependent response of Chk2 to increasing amounts of DNA damage.

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