Molecular Analysis of the Kinetochore-Microtubule Interface

描述（由申请人提供）：人体中的每个细胞包含46个不同的染色体，大单位的DNA编码指令细胞生长，分裂，并执行其特殊功能。在有丝分裂过程中，当细胞分裂时，这些染色体中的每一条都必须准确地分布到两个新的子细胞中。如果这个过程在单个染色体上发生错误，那么产生的子细胞将失去或获得数千个基因和它们所包含的指令。这种类型的染色体分离错误可导致细胞死亡，并被认为有助于肿瘤的发生。事实上，超过70%的肿瘤被观察到有异常数量的染色体。除了改变整个染色体数目的错误外，在细胞机制与染色体产生不适当的附着的情况下，这可能导致细胞分裂期间染色体断裂。这些错误已被证明会引起染色体重排，这也有可能导致细胞转化和肿瘤发生。为了在有丝分裂过程中促进DNA的分离，染色体必须产生物理附着在称为微管的棒状聚合物上，微管提供了染色体移动的结构和力量。在染色体分离中起关键作用的是一种称为着丝点的大型蛋白质结构，它形成染色体和微管之间的界面。预测着丝粒活性的抑制可靶向癌细胞，同时避免与微管结合化疗相关的剂量限制性神经元毒性。确定着丝点功能的分子基础对于理解导致肿瘤细胞产生的缺陷过程以及评估诊断和治疗的最佳靶点至关重要

DESCRIPTION (provided by applicant): Each cell in the human body contains 46 different chromosomes, large units of DNA that encode instructions for that cell to grow, divide, and carry out its specialized functions. During mitosis, when a cell divides, each of these chromosomes must be accurately distributed to the two new daughter cells. If this process occurs incorrectly for even a single chromosome, the resulting daughter cells will lose or gain thousands of genes and the instructions that they contain. This type of error in chromosome segregation can result in the death of the cell and is thought to contribute to tumorigenesis. Indeed, more than 70% of tumors are observed to have abnormal numbers of chromosomes. In addition to errors that alter whole chromosome numbers, in cases where the cellular machinery makes inappropriate attachments to the chromosomes, this can result in chromosome fragmentation during cell division. These errors have been shown to cause chromosomal rearrangements, which also have the potential to result in cellular transformation and tumorigenesis. To facilitate the segregation of DNA during mitosis, chromosomes must generate physical attachments to rod-like polymers termed microtubules that provide the structure and forces to move the chromosomes. A key player in chromosome segregation is a large proteinaceous structure termed the kinetochore that forms the interface between chromosomes and microtubules. Inhibition of kinetochore activities is predicted to target cancer cells while avoiding the dose-limiting neuronal toxicity associated with microtubule-binding chemotherapeutics. Determining the molecular basis for kinetochore function is crucial to understand the defective processes that can give rise to tumor cells, and to evaluate the best targets for the diagnosis and treatment of disease. The proposed work will analyze the mechanisms by which kinetochores interact with spindle microtubule polymers in human cells. We will take parallel cellular and biochemical approaches to analyze the key proteins that bind to microtubules at kinetochores. A key focus of this work will be not only to analyze the functions and activities of the individual proteins, but also to test how the multiple different proteins that are present at kinetochores act together in a integrated manner to form robust interactions with microtubules.