Authors:
Mark R. Dowling, Andrey Kan, Susanne Heinzel, Jie H. S. Zhou, Julia M. Marchingo, Cameron J. Wellard, John F. Markham, and Philip D. Hodgkin
Summary:
Stochastic variation in cell cycle time is a consistent feature of otherwise similar cells within a growing population. Classic studies concluded that the bulk of the variation occurs in the G1 phase, and many mathematical models assume a constant time for traversing the S/G2/M phases. By direct observation of transgenic fluorescent fusion proteins that report the onset of S phase, we establish that dividing B and T lymphocytes spend a near-fixed proportion of total division time in S/G2/M phases, and this proportion is correlated between sibling cells. This result is inconsistent with models that assume independent times for consecutive phases. Instead, we propose a stretching model for dividing lymphocytes where all parts of the cell cycle are proportional to total division time. Data fitting based on a stretched cell cycle model can significantly improve estimates of cell cycle parameters drawn from DNA labeling data used to monitor immune cell dynamics.
Source:
Proceedings of the National Academy of Sciences of the United States of America; Vol. 111, No. 17, 6377-6382 (04/29/14)