Related Experiment Videos
The mitotic spindle and DNA damage-induced apoptosis
P A Johnson1, P Clements, K Hudson
1School of Biological Sciences, G.38 Stopford Building, University of Manchester, Oxford Road, Manchester, UK.
Toxicology Letters
|March 18, 2000
Summary
Chinese hamster ovary EM9 cells, unable to repair DNA strand breaks from ethyl methanesulphonate (EMS), undergo apoptosis. Mitotic spindle assembly or checkpoint progression is crucial for this cell death pathway.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- DNA strand breaks are critical lesions that can arise from endogenous and exogenous agents.
- Certain cell lines, such as EM9 Chinese hamster ovary cells, exhibit deficient DNA repair mechanisms.
- Alkylating agents like ethyl methanesulphonate (EMS) are known to induce DNA strand breaks.
Purpose of the Study:
- To investigate the cellular response of EM9 cells to DNA strand breaks induced by EMS.
- To elucidate the role of cell cycle progression and mitotic events in the apoptosis of DNA-damaged cells.
Main Methods:
- Treatment of EM9 Chinese hamster ovary cells with ethyl methanesulphonate (EMS).
- Cell cycle synchronization and analysis of mitotic progression.
- Induction of mitotic spindle dysfunction using nocodazole.
- Assessment of apoptosis and DNA replication.
Main Results:
- EMS-treated EM9 cells exhibited prolonged G2 arrest, followed by abnormal mitosis and apoptosis.
- Cells treated in G1 phase entered mitosis with significant delay and morphological abnormalities.
- Nocodazole treatment significantly reduced apoptosis and permitted a second round of DNA replication.
Conclusions:
- The inability of EM9 cells to rejoin DNA strand breaks leads to cell cycle arrest and apoptosis.
- Mitotic spindle assembly and progression through the mitotic checkpoint are critical determinants of apoptosis following DNA strand breakage.