Quantitative studies of cell cycle checkpoints and switches

描述（由申请人提供）：本研究的长期目标是定量了解真核细胞周期的调控，这是最基本和最复杂的生物过程之一。本课题的具体目标是通过数学建模和定量实验的紧密结合，构建、分析和验证出芽酵母酵母中几个关键细胞周期检查点和开关以及整个细胞周期网络的数学模型。细胞周期检查点和开关在确保细胞周期机制的精确和稳健执行方面发挥着重要作用。它们的缺陷，例如由于遗传扰动，可导致不适当的细胞增殖或染色体分离错误，这通常与肿瘤发生有关。这项工作将有助于对酵母细胞周期调控的更深入、定量和系统水平的理解，其研究对我们对高等生物细胞周期控制和癌症机制的认识产生深远的影响。这里将运用动力系统理论的概念和方法来分析和理解这个复杂的系统。使用微流控装置的定量单细胞分析将建立起来，为数学模型生成数据并测试模型预测。具体目标是：(1)酵母细胞周期网络的全局计算分析-将对酵母细胞周期网络进行系统的计算分析，以研究系统的全局动态特性和结构稳定性，以确定系统对哪种扰动具有鲁棒性，哪些不具有鲁棒性。(2) G1检查点作为固定点的定量研究——计算模型和定量实验将一起用于研究G1逮捕的稳定性和可能增加或降低这种稳定性的网络扰动。检验了检查点是动力系统不动点的假设。(3) G1/S开关的定量研究——计算模型和定量实验将一起用于研究S相进入的类开关行为。电路拓扑在确保稳健性开关行为中的作用将被研究。(4)主轴装配检查点和M/A切换的定量研究——将采用计算建模和定量实验相结合的方法来研究检查点捕获和切换动力学的稳定性，重点研究多个反馈回路各自和协同作用。

DESCRIPTION (provided by applicant): The long-term goal of this research is to gain a quantitative understanding of the regulation of the eukaryotic cell cycle, one of the most fundamental and complex biological processes. The specific goal of this proposal is to construct, analyze and validate mathematical models for several key cell cycle checkpoints and switches as well as for the entire cell cycle network in the budding yeast Saccharomyces cerevisiae, through a close coupling between mathematical modeling and quantitative experimentation. Cell cycle checkpoints and switches play essential roles in ensuring precise and robust execution of the cell cycle machinery. Defects in them, e.g. due to genetic perturbations, can lead to inappropriate cell proliferation or errors in chromosome segregation, which are commonly associated with tumorigenesis. This work will contribute to a deeper, quantitative and systems level understanding of the yeast cell cycle regulation, the studies of which have profoundly impacted on our knowledge about cell cycle control in higher organisms and on the mechanisms of cancer. Concepts and methods from dynamical systems theory will be applied here to analyze and comprehend this complex system. Quantitative single-cell assays using microfluidic devices will be set up to generate data for the mathematical model and to test the model predictions. The specific aims are: (1) Global computational analyses of the yeast cell cycle network - Systematic computational analyses on the yeast cell cycle network will be carried out to investigate the global dynamic properties and the structural stability of the system to identify what kinds of perturbations the system is robust to and what is not. (2) Quantitative study of the G1 checkpoint as a fixed point - Computational models and quantitative experiments will be used together to investigate the stability of the G1 arrest and the network perturbations that can increase or decrease this stability. The hypothesis that the checkpoint is a dynamical system's fixed point will be tested. (3) Quantitative study of the G1/S switch - Computational models and quantitative experiments will be used together to investigate the switch-like behavior in S-phase entry. The role of the circuit topology in ensuring a robust switching behavior will be studied. (4) Quantitative study of the spindle assembly checkpoint and the M/A switch - Computational modeling and quantitative experiments will be used together to investigate the stability of the checkpoint arrest and the switching dynamics, focusing on the respective and synergistic roles of the multiple feedback loops.