Modeling Microtubule Dynamics in Mitosis

描述(申请人提供)：在细胞分裂中，许多分子的作用被整合起来，通过与动粒微管动力学直接耦合的运动，将两个完整的基因组机械地相互分离。随着分子生物学和活的荧光蛋白转基因细胞的高分辨率数字光学显微镜的融合，与细胞分裂相关的分子水平信息的程度已经显著增加。现在的一个主要挑战是从大量的定量分子水平数据中了解细胞水平的机制。重要的是，单个动粒微管的动态行为仍有待确定。幸运的是，高速计算的进步使模拟微管动态不稳定和相关的染色体运动等复杂过程变得越来越实用。这个项目的目标将是开发基于计算机的模型来测试有丝分裂中控制动粒微管动力学的机制的假说。具体地说，我们将开发计算模型来预测发芽酵母有丝分裂中基于马达的极射射力、稳定的化学梯度和机械张力的单独和联合影响。我们还将开发产生假设的化学梯度的反应-扩散模型，开发在这种梯度中微管行为的理论，并在LLCPK细胞中测试该理论。此外，我们将开发一个集成的微管嵌入发芽酵母动粒的机械力化学模型，并测试动粒上的机械力如何影响微管的稳定性。在所有情况下，模型都将在与细胞生物学家的持续合作中开发，并将预测直接与实验观察进行比较。为了便于这些定量比较，我们将实施高分辨率光学显微镜模型，以产生活细胞中荧光分子的合成数字图像，并直接将模型预测的统计数据与实验获得的统计数据进行比较。

DESCRIPTION (provided by applicant): In cell division the actions of many molecules are integrated to mechanically segregate two complete genomes from each other via motions directly coupled to the dynamics of kinetochore microtubules. The extent of molecular-level-information relevant to cell division has increased substantially with the convergence of molecular biology and high-resolution digital light microscopy of living fluorescent protein- transfected cells. A major challenge now is to develop an understanding of cellular-level mechanisms from the vast amounts of quantitative molecular-level data. Importantly, the dynamic behavior of individual kinetochore microtubules remains to be determined. Fortunately, advances in high-speed computing make it increasingly practical to model complex processes such as microtubule dynamic instability and associated chromosome motions. The objective of this project will be to develop computer-based models to test hypotheses for the mechanisms controlling kinetochore microtubule dynamics in mitosis. Specifically, we will develop computational models to predict the separate and combined effects of motor-based polar ejection forces, stable chemical gradients, and mechanical tension in budding yeast mitosis. We will also develop reaction-diffusion models that generate the hypothesized chemical gradients, develop a theory for microtubule behavior in such gradients, and test the theory in LLCPK cells. In addition, we will develop an integrated mechanochemical model of microtubules embedded in the budding yeast kinetochore and test how mechanical force on the kinetochore can affect microtubule stability. In all cases models will be developed in ongoing collaborations with cell biologists, and the predictions compared directly to experimental observations. To facilitate these quantitative comparisons, we will implement models of high- resolution light microscopy to produce synthetic digital images of the fluorescent molecules in living cells and directly compare the model-predicted statistics to those obtained experimentally.