MODELING THE FERTILIZATION CALCIUM WAVE IN MOUSE EGGS

这个提议的总体目标是建立一个小鼠卵母细胞和卵子的现实空间模型，这将使我能够研究成熟和受精的潜在机制。然后，我将使用这个模型来回答一个非常简单的问题：未成熟的卵母细胞在成熟过程中发生了什么，使其具有受精能力，一旦受精，这些成熟诱导的变化对随后的钙信号有何重要性？一段时间以来，人们已经知道，在成熟过程中，卵母细胞增加其释放钙的能力，并且已经提出了许多潜在的机制：1）ER的钙螯合能力增加; 2）通过增加Ip 3受体的数量和/或密度来增加ER释放钙的能力; 3）由于ER的结构重排，ER在特定空间区域中有差异地螯合和/或释放钙的能力增加; 4）由于内流，总细胞内钙增加;和5）IP 3受体敏感性的变化。借助于该模型的成熟和受精机制的结合，我将通过检查这些变化对受精前和受精后卵子的影响来测试这些假设，并将它们与实验进行比较。此外，我将使用该模型来研究受精波的启动和传播的机制，类似于我以前对非洲爪蟾的工作。最后，我将进行有限的实验室实验，在合理的情况下，收集数据的模型校准，并可能，模拟结果的比较，当这些数据在文献中不可用。建模和模拟将与Les Loew博士和CBIT的其他人合作进行，实验工作将大大有助于与Laurinda Jaffe博士实验室成员的合作。

The overall goal of this proposal is to develop a realistic spatial model of the mouse oocyte and egg, that will allow me to examine the mechanisms underlying maturation and fertilization. I will then use this model to answer a very simple question: what happens to the immature oocyte during maturation that makes it fertilizable, and once it is fertilized, how are these maturation-induced changes important for the ensuing calcium signal? It has been known for some time that during maturation, the oocyte increases its capability to release calcium, and a number of potential mechanisms have been proposed: l) an increase in the ER's calcium-sequestering capability; 2) an increase in the ER's ability to release calcium via an increase in the number and/or density of Ip3 receptors; 3) an increase in the ER's ability to sequester and/or release calcium differentially in specific spatial regions as a result of structural rearrangement of the ER; 4) an increase in total intracellular calcium due to influx; and 5) a change in the IP3 receptor sensitivity. By dint of the model's incorporation of both maturation and fertilization mechanisms, I will test these hypotheses by examining the effects of such changes on both the pre-fertilization and post-fertilization egg, and comparing them to experiment. Additionally, I will use the model to investigate the mechanisms underlying the initiation and propagation of the fertilization wave, in a manner similar to my previous work with Xenopus. Finally, I will perform limited laboratory experiments, when reasonable, to collect data for both model calibration and, possibly, comparison of simulation results, when such data are not available in the literature. The modeling and simulation will be performed in collaboration with Dr. Les Loew and others in CBIT, and the experimental work will be greatly aided by collaboration with members of Dr. Laurinda Jaffe's lab.