Depletion of Chk1 Leads to Premature Activation of Cdc2-cyclin B and Mitotic Catastrophe

Naoki Takeda,Makoto Nakanishi,Shinji Tsuge,Hiroyuki Niida,Akimitsu Konishi,Yuko Katsuno

doi:10.1074/jbc.m505009200

Naoki Takeda, Makoto Nakanishi + Show 4 more

Open Access

https://doi.org/10.1074/jbc.m505009200

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Abstract

Mitotic catastrophe occurs as a result of the uncoupling of the onset of mitosis from the completion of DNA replication, but precisely how the ensuing lethality is regulated or what signals are involved is largely unknown. We demonstrate here the essential role of the ATM/ATR-p53 pathway in mitotic catastrophe from premature mitosis. Chk1 deficiency resulted in a premature onset of mitosis because of abnormal activation of cyclin B-Cdc2 and led to the activation of caspases 3 and 9 triggered by cytoplasmic release of cytochrome c. This deficiency was associated with foci formation by the phosphorylated histone, H2AX (gammaH2AX), specifically at S phase. Ectopic expression of Cdc2AF, a mutant that cannot be phosphorylated at inhibitory sites, also induced premature mitosis and foci formation by gammaH2AX at S phase in both embryonic stem cells and HCT116 cells. Depletion of ATM and ATR protected against cell death from premature mitosis. p53-deficient cells were highly resistant to lethality from premature mitosis as well. Our results therefore suggest that ATM/ATR-p53 is required for mitotic catastrophe that eliminates cells escaping Chk1-dependent mitotic regulation. Loss of this function might be important in mammalian tumorigenesis.

Highlights

Mitotic catastrophe was first identified in certain mutant fission yeast strains as a lethal phenotype characterized by gross abnormalities in chromosome segregation during mitosis [5, 6]
A recent study demonstrated that mitotic catastrophe induced by DNA damage is dependent on caspase activation, suggesting that it constitutes a special case of apoptosis [14, 15]
Chk1 Deficiency Causes DNA Damage during S Phase in a Manner Dependent on Active Cyclin B-Cdc2—To determine whether apoptosis induced by premature mitosis is because of DNA damage, we examined the foci formation of phospho-H2AX (␥H2AX), a robust marker for cellular DSBs [26]

Summary

Introduction

Mitotic catastrophe was first identified in certain mutant fission yeast strains as a lethal phenotype characterized by gross abnormalities in chromosome segregation during mitosis [5, 6]. Chk1 Deficiency Causes DNA Damage during S Phase in a Manner Dependent on Active Cyclin B-Cdc2—To determine whether apoptosis induced by premature mitosis is because of DNA damage, we examined the foci formation of phospho-H2AX (␥H2AX), a robust marker for cellular DSBs [26]. These results suggested that premature mitosis induced by Chk1 depletion causes DNA damage, possibly DSBs. In yeast, DNA replication checkpoint kinases stabilize DNA replication fork progression during S

Results

Conclusion