Organization of the Mammalian Mitotic Spindle

描述（由申请人提供）：准确的染色体分离对物种繁殖和细胞活力至关重要，并由称为纺锤体的复杂微管结构驱动。密集的生化、遗传和蛋白质组学研究提供了参与纺锤体组织和纺锤体依赖性染色体运动的蛋白质的广泛目录。然而，这些努力并没有揭示哺乳动物细胞中确保忠实染色体分离的分子机制。最近，我们发现人类肿瘤细胞中染色体错误分离的最常见原因是着丝点微管（K- MT）附着错误的持续存在。然而，我们对如何调节K-MT附件以促进错误纠正的理解仍然明显不完整。我们不明白不同的分子成分是如何在细胞周期转变过程中产生一致的输出来微调K-MT附着稳定性的。我们也不知道非整倍性是如何影响基因组稳定性和细胞存活的。在即将到来的资助期内，我们的目标是结合生化方法和活细胞成像来测试模型，并确定有丝分裂中K-MT附着物的调节机制。了解这些机制可以为癌症治疗带来新的治疗方法。本提案的具体目的是：1)利用活细胞成像技术确定前期到中期的生化变化；2)。将活细胞成像与分子工具相结合，测试单基因拷贝数的变化足以通过破坏K-MT附着动力学来破坏忠实的染色体分离的模型；3)。量化持续性K-MT附着错误造成的遗传损伤；和4)。在活体动物中测试抑制非整倍体细胞生长的机制。

DESCRIPTION (provided by applicant): Accurate chromosome segregation is essential for the propagation of species and the viability of cells, and is driven by a complex microtubule-based structure called the spindle. Intensive biochemical, genetic, and proteomic efforts provide an extensive catalogue of proteins that participate in spindle organization and spindle-dependent chromosome movement. However, these efforts don't reveal the molecular mechanisms that ensure faithful chromosome segregation in mammalian cells. Recently, we showed that the most common cause of chromosome mis-segregation in human tumor cells is the persistence of kinetochore-microtubule (K- MT) attachment errors. However, our understanding for how K-MT attachments are regulated to promote error correction remains starkly incomplete. We don't understand how different molecular components create a coherent output to fine-tune K-MT attachment stability during cell cycle transitions. We also don't understand how aneuploidy influences genome stability and cell survival. It is our goal in the forthcoming funding period to combine biochemical methods and live cell imaging to test models and determine the mechanisms of the regulation of K-MT attachments in mitosis. Understanding these mechanisms could lead to new therapeutic approaches for cancer treatment. The specific aims of this proposal are, 1.) To use live cell imaging to determine the biochemical changes underlying the transition from prometaphase to metaphase; 2.) To combine live cell imaging with molecular tools to test the model that changes in the copy number of single genes is sufficient to undermine faithful chromosome segregation by disrupting K-MT attachment dynamics; 3.) To quantify the genetic damage caused by persistent K-MT attachment errors; and 4.) To test mechanisms that suppress aneuploid cell growth in live animals.