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Cycle delay in irradiated cytochalasin-induced polykaryons. Does cytoskeleton status affect cell cycle checkpoints?
1Radiation Science Laboratory, Velindre Hospital, Cardiff, Wales, United Kingdom.
Cell Biology International
|January 1, 1995
Summary
Irradiation causes cell cycle delays in normal cells but not in giant cells lacking cytokinesis. This suggests that inhibiting cell division alters cell cycle checkpoints, possibly due to damage tolerance or cytoskeletal changes.
Area of Science:
- Cell Biology
- Radiation Biology
- Molecular Biology
Background:
- Ionizing radiation is a known inducer of cell cycle arrest.
- Cell cycle checkpoints are crucial for maintaining genomic stability.
- Cytokinesis is the final stage of cell division, ensuring daughter cells are viable.
Purpose of the Study:
- To investigate the effect of inhibiting cytokinesis on the G2 cell cycle delay induced by irradiation.
- To explore the role of cell cycle checkpoints in response to DNA damage when cytokinesis is blocked.
Main Methods:
- Exposure of Chinese Hamster Ovary (CHO-K1) cells to 137Cs irradiation up to 20 Gray (Gy).
- Induction of giant cells using cytochalasin B to inhibit cytokinesis.
- Analysis of cell cycle progression, specifically the G2 phase and the 2C-8C transition.
Main Results:
- Irradiation induced a significant G2 delay in normally dividing CHO-K1 cells.
- Cells induced to become giant (cytokinesis inhibited) showed a minimal delay in the 2C-8C transition.
- This indicates that cytokinesis inhibition modifies cell cycle checkpoint responses to irradiation.
Conclusions:
- Inhibition of cytokinesis alters the cell cycle checkpoint response to irradiation-induced DNA damage.
- This modification may be attributed to damage tolerance mechanisms.
- Alternatively, cytoskeletal reorganization that prevents cytokinesis could trigger feedback loops affecting cell cycle control.