DNA replication is required for the checkpoint response to damaged DNA in <i>Xenopus</i> egg extracts

Stokes, Matthew P.; Hatten, Ruth Van; Lindsay, Howard D.; Michael, W. Matthew

doi:10.1083/jcb.200204127

Cited by 71 publications

(82 citation statements)

References 41 publications

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“…These observations are potentially very interesting, but it is not clear at present how they fit in the overall picture of the S phase checkpoint indicated in Figure 3. Evidence accumulates for parallel pathways that cooperate to inhibit DNA replication after exposure to IR (Falck et al, 2002), and it is relevant to recall recent studies suggesting a requirement for active DNA replication in S phase checkpoint activation (Lupardus et al, 2002;Stokes et al, 2002).…”

Section: Molecular Mechanisms Of the S Phase Checkpointmentioning

confidence: 99%

DNA damage checkpoint control in cells exposed to ionizing radiation

et al. 2003

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Damage induced in the DNA after exposure of cells to ionizing radiation activates checkpoint pathways that inhibit progression of cells through the G1 and G2 phases and induce a transient delay in the progression through S phase. Checkpoints together with repair and apoptosis are integrated in a circuitry that determines the ultimate response of a cell to DNA damage. Checkpoint activation typically requires sensors and mediators of DNA damage, signal transducers and effectors. Here, we review the current state of knowledge regarding mechanisms of checkpoint activation and proteins involved in the different steps of the process. Emphasis is placed on the role of ATM and ATR, as well on CHK1 and CHK2 kinases in checkpoint response. The roles of downstream effectors, such as P53 and the CDC25 family of proteins, are also described, and connections between repair and checkpoint activation are attempted. The role of checkpoints in genomic stability and the potential of improving the treatment of cancer by DNA damage inducing agents through checkpoint abrogation are also briefly outlined.

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Section: Molecular Mechanisms Of the S Phase Checkpointmentioning

confidence: 99%

DNA damage checkpoint control in cells exposed to ionizing radiation

et al. 2003

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“…The mechanism of ATR activation is presently unknown, but if the lesions sensed by ATR do not induce any global changes to chromatin, and/or if they require processing by a replication fork or damage repair pathway before detection, then a comparable all-or-nothing checkpoint response involving ATR might not be expected. In budding yeast and Xenopus, checkpoint activation by MMS requires active replication forks (31)(32)(33). Experiments in yeast indicate that the activation of Rad53 in response to HU and MMS requires some threshold number of forks (34).…”

Section: Effects Of Ir Mms and Hu On Replication Dynamics: Mammaliamentioning

confidence: 99%

Visualization of Altered Replication Dynamics after DNA Damage in Human Cells

Merrick

Jackson

Diffley

2004

Journal of Biological Chemistry

211

186

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Eukaryotic cells respond to DNA damage within the S phase by activating an intra-S checkpoint: a response that includes reducing the rate of DNA synthesis. In yeast cells this can occur via checkpoint-dependent inhibition of origin firing and stabilization of ongoing forks, together with a checkpoint-independent slowing of fork movement. In higher eukaryotes, however, the mechanism by which DNA synthesis is reduced is less clear. We have developed strategies based on DNA fiber labeling that allow the quantitative assessment of rates of replication fork movement, origin firing, and fork stalling throughout the genome by examining large numbers of individually labeled replication forks. We show that exposing S phase cells to ionizing radiation induces a transient block to origin firing but does not affect fork rate or fork stalling. Alkylation damage by methyl methane sulfonate causes a slowing of fork movement and a high rate of fork stalling, in addition to inducing a block to new origin firing. Nucleotide depletion by hydroxyurea also reduces replication fork rate and increases stalling; moreover, in contrast to a recent report, we show that hydroxyurea induces a strong block to new origin firing. The DNA fiber labeling strategy provides a powerful new approach to analyze the dynamics of DNA replication in a perturbed S phase.

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“…It has usually been analysed by hydroxyurea (HU) treatment of the cells, which inhibits ribonucleotide reductase and consequently DNA synthesis. DNA damage induced by UV light or methyl methanesulphonate (MMS) treatment blocks DNA replication fork progression and as a consequence also activates the DNA replication checkpoint (Lupardus et al, 2002;Stokes et al, 2002). How partially replicated DNA is detected is still unknown, but several observations suggest that the signal arises from the replication machinery itself (D'Urso et al, 1995;Michael et al, 2000;You et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

ATM/ATR-independent inhibition of cyclin B accumulation in response to hydroxyurea in nontransformed cell lines is altered in tumour cell lines

2003

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The DNA replication checkpoint is an inhibitory pathway ensuring that mitosis occurs only after completion of DNA synthesis. Its function may be relevant to the stability of the genome. The essential elements of this checkpoint are ATM/ATR kinases that indirectly lead to the phosphorylation and inhibition of the mitosis-promoting factor (Cdc2/cyclin B1). The function of this checkpoint was analysed in diverse nontransformed and tumour-derived cell lines. All cell lines tested arrested mitosis entry when DNA synthesis was inhibited by hydroxyurea (HU) treatment. But, unlike what has been described in yeast and Xenopus, in normal rat kidney (NRK) cells and NIH 3T3 fibroblasts, the arrest induced by HU treatment was not abrogated by caffeine, an ATM and ATR inhibitor. This indicated the presence of an ATM/ATR-independent response to DNA synthesis inhibition in these nontransformed mammalian cell lines. Interestingly, the behaviour of different tumour cell lines after caffeine treatment varied. While SW480, NP29, NP18 and HeLa cells did not enter mitosis in the presence of caffeine after HU treatment, in CaCo2, DLD1, HCT116 and HT29 caffeine abrogated the checkpoint response. In nontransformed cell lines, lack of cyclin B1 accumulation was observed when DNA synthesis was inhibited. This response was not abrogated by caffeine. In the tumour cell lines, a good correlation between the ability to arrest cell cycle when DNA synthesis was inhibited in the presence of caffeine and the lack of cyclin B1 accumulation was observed. Thus, there is an ATM/ATR-independent checkpoint response that leads to a decrease in cyclin B1 accumulation. However, this response is not functional in some tumour cell lines. Using inhibitors of p38a and b, Mek1, 2 and p53À/À knocked-out fibroblasts, we showed that these proteins were also not involved in this particular checkpoint response. Lack of cyclin B1 accumulation after DNA synthesis inhibition in NRK cells was not due to increased degradation of the protein, but correlated with a decrease in mRNA accumulation.

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DNA replication is required for the checkpoint response to damaged DNA in Xenopus egg extracts

Cited by 71 publications

References 41 publications

DNA damage checkpoint control in cells exposed to ionizing radiation

DNA damage checkpoint control in cells exposed to ionizing radiation

Visualization of Altered Replication Dynamics after DNA Damage in Human Cells

ATM/ATR-independent inhibition of cyclin B accumulation in response to hydroxyurea in nontransformed cell lines is altered in tumour cell lines

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