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Quasi-exponential generation time distributions from a limit cycle oscillator.
Cell and Tissue Kinetics
|May 1, 1985
Summary
Animal cells exhibit precise cell cycle timing, not random behavior. A new model explains this precise timekeeping and periodic cell cycle events, reconciling stochastic and periodic behaviors.
Area of Science:
- Cell biology
- Biophysics
- Systems biology
Background:
- Cell generation times often appear random and exponentially distributed.
- Despite apparent randomness, evidence suggests precise timekeeping in the cell cycle.
- Observed clustering of cell generation times at approximately 4-hour intervals.
Purpose of the Study:
- To investigate the precise timekeeping mechanisms within the cell cycle.
- To reconcile the stochastic and periodic behaviors observed in animal cell cycles.
- To present a cell cycle model that explains observed phase shift response data.
Main Methods:
- Time-lapse video-tape microscopy to observe cell generation times.
- Analysis of phase shift responses to external stimuli (heat shock, radiation, serum pulses).
- Development of a mathematical model for cell cycle control.
Main Results:
- Cell generation times were observed to cluster at approximately 4-hour intervals, deviating from a smooth distribution.
- Phase shift responses to various stimuli showed a pattern that repeated twice in cells with an 8-9 hour modal generation time.
- The proposed model successfully accounts for the phase response data.
Conclusions:
- Animal cells possess an independent cellular clock that governs cell cycle events.
- This clock reconciles the seemingly contradictory stochastic and periodic behaviors of cell cycles.
- The model provides a framework for understanding precise timekeeping in cell proliferation.