Wee Kinases and the Control of the Meiotic Cell Cycle

 描述（由申请人提供）：本提案的总体目标是了解控制进入和退出减数分裂细胞周期的机制。了解生殖细胞减数分裂复制的调控有助于确定细胞如何分裂。蛋白质磷酸化级联反应的基本概念主要来自减数分裂的研究，蛋白质磷酸化级联反应是细胞通过分裂的不同阶段的中继，检查点是监测关键事件的完成并延迟进展到下一阶段。这些知识提供了对发育和疾病过程的更好理解，并开辟了靶向细胞周期调节剂的药理学新篇章。通过研究小鼠卵母细胞减数分裂进程的调控，我们已经确定了哺乳动物减数分裂成熟所必需的新成分。最重要的是，我们提供的证据表明，磷酸化网络是一样重要的蛋白质降解的控制进入中期I（MI）和退出第二中期（MII）在小鼠卵母细胞。我们现在建议进一步了解这些途径是如何参与细胞周期的不同步骤，并通过沿着以下三个具体目标组织实验。在第一个具体目标中，我们将调查 我们已经证明，在卵母细胞减数分裂的不同步骤中，激酶（Wee 1B）的刺激性和抑制性磷酸化是至关重要的。我们将检验这一假设，即在MI期间，这种酶的活性通过抑制位点的磷酸化而受到抑制。第二个具体目标将致力于了解激酶/磷酸酶如何在MII停滞期间产生和维持磷酸化网络，以及这些网络中的变化如何触发MII退出。在第三个具体目标中，我们将研究蛋白质的稳定性和翻译调控 有助于组装和维持这些参与MII停滞和MII退出的激酶/磷酸酶网络。更好地了解这些过程将提供新的见解减数分裂细胞周期的调节和线索如何退出减数分裂失败可能会导致异常的染色体运输，分离，和受损的胚胎发育。它还将确定新的调控网络，可以被靶向操纵细胞复制。

 DESCRIPTION (provided by applicant): The overall aim of this proposal is to understand the mechanism that controls entry and exit from the meiotic cell cycle. Understanding the regulation of the germ cell meiotic replication has been instrumental in defining how cells divide. Basic concepts on the cascade of protein phosphorylation that relays a cell through different phases of division, and the checkpoints that monitor completion of critical events and delay progression to the next stage, come largely from studies on meiosis. This knowledge has provided a better understanding of processes involved in development and disease, and has opened a new chapter of pharmacology that targets cell cycle regulators. By investigating the regulation of meiotic progression in mouse oocytes, we have identified novel components essential for meiotic maturation in mammals. Most importantly, we have provided evidence that networks of phosphorylation are as important as protein degradation in the control of entry into metaphase I (MI) and exit from the second metaphase (MII) in mouse oocytes. We now propose to further understand how these pathways are involved in different steps of the cell cycle with experiments organized along the following three Specific Aims. With the first Specific Aim, we will investigate stimulatory and inhibitory phosphorylation of a kinase (Wee1B) which we have shown to be critical at different steps of oocyte meiosis. We will test the hypothesis that the activity of thi enzyme is repressed during MI via phosphorylation at inhibitory sites. The Second Specific aim will be devoted to understanding how kinases/phosphatases generate and maintain networks of phosphorylation during MII arrest and how MII exit is triggered by changes in these networks. With the third Specific Aim, we will investigate how protein stability and translational regulation contribute to assemble and maintain these networks of kinases/phosphatases involved in MII arrest and MII exit. A better understanding of these processes will provide novel insight into the regulation of the meiotic cell cycle and clues on how failure to exit meiosis may lead to aberrant chromosome trafficking, segregation, and compromised embryo development. It will also identify new regulatory networks that can be pharmacologically targeted to manipulate cell replication.