Does the potential for chaos constrain the embryonic cell-cycle oscillator?
Does the potential for chaos constrain the embryonic cell-cycle oscillator?
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DOI：
10.1371/journal.pcbi.1002109
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发表时间：
2011-07
影响因子：
4.3
通讯作者：
Wingreen NS
中科院分区：
文献类型：
--
作者：
McIsaac RS;Huang KC;Sengupta A;Wingreen NS
Although many of the core components of the embryonic cell-cycle network have been elucidated, the question of how embryos achieve robust, synchronous cellular divisions post-fertilization remains unexplored. What are the different schemes that could be implemented by the embryo to achieve synchronization? By extending a cell-cycle model previously developed for embryos of the frog Xenopus laevis to include the spatial dimensions of the embryo, we establish a novel role for the rapid, fertilization-initiated calcium wave that triggers cell-cycle oscillations. Specifically, in our simulations a fast calcium wave results in synchronized cell cycles, while a slow wave results in full-blown spatio-temporal chaos. We show that such chaos would ultimately lead to an unpredictable patchwork of cell divisions across the embryo. Given this potential for chaos, our results indicate a novel design principle whereby the fast calcium-wave trigger following embryo fertilization synchronizes cell divisions. Cell divisions across an embryo occur in rapid synchrony - like clockwork - starting within minutes of fertilization. How does an embryo achieve this remarkable uniformity? Simple diffusion is too slow: typical proteins diffuse with a rate of 10 µm2/s, requiring nearly 14 hours to traverse a 1 mm embryo. An exciting idea is that the embryo is an active medium, much like the heart where pulses of electrical activity result in organized contractions. However, just as the heart can have arrhythmias, our model predicts that oscillations in the embryo can become chaotic. What would be the biological consequences of this behavior? How do embryos avoid chaos? Our work provides potential answers to these questions: Chaos would lead to an unpredictable patchwork of cell divisions across the embryo - clearly a fatal defect in development. To avoid chaos then, we predict that cell-cycle oscillations need to be triggered throughout the embryo at almost precisely the same time. The threat that chaos will mar development therefore explains the mystery of why embryos universally employ a fast calcium wave to trigger cell-cycle oscillations. In this way, developing organisms get the synchronizing benefits of an active medium without suffering the destructive consequences of chaotic arrhythmias.
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影响因子：
64.5
作者：
KING, RW;PETERS, JM;KIRSCHNER, MW
通讯作者：
KIRSCHNER, MW
DOI：
10.1073/pnas.0509483102
发表时间：
2005-12-20
影响因子：
11.1
作者：
Gregor, T;Bialek, W;Wieschaus, EF
通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
3.2
作者：
Elowitz, MB;Surette, MG;Leibler, S
通讯作者：
Leibler, S
影响因子：
4
作者：
Schmidt, A;Rauh, NR;Mayer, TU
通讯作者：
Mayer, TU