Kinetochore Spindle Interaction in Fission Yeast

描述(由申请人提供)：在有丝分裂中，染色体的均匀分离需要染色体和有丝分裂纺锤体之间的适当相互作用。动点是组装在着丝粒DNA上的一种特殊结构，它介导着染色体和纺锤体微管之间的连接。不同生物体的动点在它们的结构上有很大的不同，但执行着基本相似的功能。关于酿酒酵母中的动粒已经有了很多的了解。然而，目前还不清楚我们能在多大程度上将这一简单点动粒的知识应用于复杂的区域动粒，如人类的动粒。这一建议的长期目标是解剖S.pombe中的动粒结构，作为区域动粒的模型，并了解动粒如何与纺锤体协调以确保在这种模式生物中染色体分离的高保真。通过对金黄色葡萄球菌、酿酒酵母和其他生物的动粒的比较和对比，我们希望描绘出动粒功能的一般生物学原理。这些知识将有助于识别肿瘤细胞中的分子损伤，这些损伤导致在几乎所有类型的肿瘤中都能检测到的高非整倍体错误染色体数量。这里提出了三个具体目标来分析分裂酵母中的动粒/纺锤体相互作用： 1.鉴定分裂酵母中正确附着所需的新的动粒和纺锤体成分。 2.鉴定新的动粒蛋白的结构和功能。 3.探讨动点在有丝分裂初期由静态亲和力向纺锤体极转变为与纺锤体MTS的动态亲和力的机制。

DESCRIPTION (provided by applicant): Equal chromosome segregation in mitosis requires proper interaction between the chromosomes and the mitotic spindle. Kinetochores are the specialized structures that are assembled on centromeric DNAs and mediate the attachment between the chromosomes and the spindle microtubules. Kinetochores of various organisms differ remarkably in their architectures and yet perform fundamentally similar functions. Much has been learnt of the kinetochores in S. cerevisiae. However, it is unclear to what extent can we apply the knowledge of this simple point kinetochore onto complex regional kinetochores such as those of humans. The long-term goal of this proposal is to dissect the kinetochore structure in S. pombe as a model of the regional kinetochores and to understand how kinetochores co-ordinate with the spindle to ensure the high fidelity of chromosome segregation in this model organism. By comparing and contrasting the kinetochores of S. pombe, S. cerevisiae and those of other organisms, we wish to delineate the general biological principles of the kinetochore functions. This knowledge will facilitate the identification of the molecular lesions in tumor cells which lead to high rate of aneuploidy - erroneous chromosome numbers that are detected in virtually all types of tumor. Three specific aims are proposed here to analyze the kinetochore/spindle interaction in fission yeast: 1. To identify novel kinetochore and spindle components in fission yeast that are required for their proper attachment. 2. To characterize the architectural and functional roles of novel kinetochore proteins. 3. To explore the mechanism of how kinetochores switch from a static affinity to spindle pole to a dynamic affinity to spindle MTs at the entry of mitosis.