Regulation of Centromere Protein Stability and Impact on Cancer Progression

 描述(申请人提供)：染色体复制和传递对于遗传特性是必不可少的，但在多细胞真核生物中，负责这些过程的机制仍然知之甚少。着丝粒是着丝粒形成所必需的，在有丝分裂和减数分裂过程中，着丝粒是纺锤体的关键附着部位。着丝粒或着丝粒功能缺陷会导致非整倍体，这是人类癌症的一个标志，也是许多出生缺陷的原因。现在着丝粒领域的一个紧迫问题是着丝粒身份是如何在多细胞真核生物中从一代传播到下一代的。我们已发表和未发表的结果表明，着丝粒染色质蛋白及其调节因子的水平受到基因表达和蛋白分解机制的严格调控，以确保着丝粒和染色体的忠实繁殖。这一建议结合了遗传、分子、细胞生物学和生化方法，利用果蝇细胞培养和动物组织来确定调节着丝粒染色质蛋白水平的分子和机制，并促进着丝粒染色质的组装和繁殖。着丝粒染色质的入口点是一种保守的组蛋白H3样蛋白(CENP-A，苍蝇中的CID)，它仅定位于功能着丝粒。我们先前确定了CENP的关键调控因子-定位和组装，以及细胞周期调控和着丝粒形成之间的联系，这为拟议的目标提供了智力和技术基础。这项提议的具体焦点是澄清 细胞周期对着丝粒蛋白稳定性的调节和错误调节的后果通过研究：1)相互保护和其他机制如何调节CID及其伴侣CAL1的稳定性，2)着丝粒蛋白调节不当对细胞、组织和生物体的影响，以及3)着丝粒蛋白调节不当如何在胶质母细胞瘤的果蝇模型中促进肿瘤的发生和发展。深入了解这些研究产生的着丝粒组装的正常调节，将提供关于这一基本生物学过程的基本信息，洞察与癌症和出生缺陷相关的非整倍体的病因学机制，并最终将导致开发与着丝粒缺陷相关的人类疾病的诊断和治疗工具，如癌症。

 DESCRIPTION (provided by applicant): Chromosome replication and transmission are essential for the inheritance of genetic traits, but the mechanisms responsible for these processes remain poorly understood in multicellular eukaryotes. The centromere is required for kinetochore formation, which serves as the key attachment site to the spindle during mitosis and meiosis. Defects in centromere or kinetochore function result in aneuploidy, which is a hallmark of human cancers and is responsible for many birth defects. A pressing question in the centromere field today is how centromere identity is propagated from one generation to the next in multicellular eukaryotes. Our published and unpublished results demonstrate that the levels of centromeric chromatin proteins and their regulators are tightly regulated by gene expression and proteolytic mechanisms to ensure faithful centromere and chromosome propagation. This proposal integrates genetic, molecular, cell biological and biochemical approaches to identify the molecules and mechanisms that regulate the levels of centromeric chromatin proteins, and promote the assembly and propagation of centromeric chromatin, using Drosophila cell culture and animal tissues. The entry point into centromeric chromatin is a conserved histone H3-like protein (CENP-A, CID in flies) that localizes exclusively to functional centromeres. We previously identified key regulators of CENP-localization and assembly, as well as a link between cell cycle regulation and centromere formation, which provide an intellectual and technical foundation for the proposed aims. The specific focus of this proposal is to elucidate the cell cycle regulation of centromeric protein stability and the consequences of misregulation by investigating: 1) how mutual protection and other mechanisms regulate the stability of CID and its chaperone CAL1, 2) the impact of centromere protein misregulation on cells, tissues and the organism, and 3) how centromere protein misregulation contributes to cancer initiation and progression in Drosophila model of glioblastoma. The deeper understanding of the normal regulation of centromere assembly generated by these studies will provide basic information about this essential biological process, insights into mechanisms responsible for the etiology of aneuploidy associated with cancer and birth defects, and ultimately will lead to the development of tools for diagnosis and treatment of human diseases associated with centromere defects, such as cancer.