Novak Bela, Pataki Zsuzsa, Ciliberto Andrea, Tyson John J.
Department of Agricultural Chemical Technology, Budapest University of Technology and Economics, Szt Gellert ter 4, 1111 Budapest, Hungary.
Chaos. 2001 Mar;11(1):277-286. doi: 10.1063/1.1345725.
Much is known about the genes and proteins controlling the cell cycle of fission yeast. Can these molecular components be spun together into a consistent mechanism that accounts for the observed behavior of growth and division in fission yeast cells? To answer this question, we propose a mechanism for the control system, convert it into a set of 14 differential and algebraic equations, study these equations by numerical simulation and bifurcation theory, and compare our results to the physiology of wild-type and mutant cells. In wild-type cells, progress through the cell cycle (G1-->S-->G2-->M) is related to cyclic progression around a hysteresis loop, driven by cell growth and chromosome alignment on the metaphase plate. However, the control system operates much differently in double-mutant cells, wee1(-) cdc25Delta, which are defective in progress through the latter half of the cell cycle (G2 and M phases). These cells exhibit "quantized" cycles (interdivision times clustering around 90, 160, and 230 min). We show that these quantized cycles are associated with a supercritical Hopf bifurcation in the mechanism, when the wee1 and cdc25 genes are disabled. (c) 2001 American Institute of Physics.
关于控制裂殖酵母细胞周期的基因和蛋白质，我们已经了解很多。这些分子成分能否组合成一个连贯的机制，来解释裂殖酵母细胞中观察到的生长和分裂行为呢？为了回答这个问题，我们提出了一种控制系统机制，将其转化为一组14个微分方程和代数方程，通过数值模拟和分岔理论研究这些方程，并将我们的结果与野生型和突变型细胞的生理学进行比较。在野生型细胞中，细胞周期进程（G1→S→G2→M）与围绕滞后环的循环进程相关，该进程由细胞生长和中期板上的染色体排列驱动。然而，在双突变细胞wee1(-) cdc25Delta中，控制系统的运作方式却大不相同，这些细胞在细胞周期的后半段（G2和M期）进程中存在缺陷。这些细胞表现出“量化”的周期（分裂间隔时间聚集在90、160和230分钟左右）。我们表明，当wee1和cdc25基因失活时，这些量化周期与该机制中的超临界霍普夫分岔有关。（c）2001美国物理研究所。
