Organization and Regulation of Eukaryotic Centromeres

描述(申请人提供)：染色体遗传确保遗传信息的传递。染色体异常分离严重影响所有细胞和生物体的健康和活力。染色体遗传错误会导致染色体异常(非整倍体)，导致许多出生缺陷，如唐氏综合症和流产，几乎是所有类型癌症的特征。着丝粒是DNA和蛋白质的复合体，是染色体遗传过程的中心，有助于动粒、异染色质和姐妹染色单体凝聚力的形成。着丝粒功能缺陷会导致酵母、苍蝇和小鼠的非整倍体或肿瘤形成。CENP-A是着丝粒核小体中取代H3的一种保守的H3-1样组蛋白，是着丝粒及其邻近着丝粒区域的结构和功能基础。我们已经证明，动粒染色质是CENP-A和H3核小体的散布结构域，促进中期染色体上的特殊圆柱形结构。这种特殊的结构是在不同的DNA序列上形成的，目前还不知道着丝粒染色质是如何建立和维持的，也不知道如果它改变了结构和功能。这项提案的目标是应用一种综合的、双系统的方法，使用我在以前的实验室开发的新试剂和技术，在果蝇和人类身上测试着丝粒染色质的关键组织和功能方面。我们建议研究基因组结构和染色质的组织和动力学在CENP-A染色质、着丝粒结构域和中期动粒结构的组装和调节中的作用。

DESCRIPTION (provided by applicant): Chromosome inheritance ensures transmission of genetic information. Abnormal chromosome segregation severely affects the health and viability of all cells and organisms. Errors in chromosome inheritance lead to chromosome abnormalities (aneuploidy) that cause many birth defects, such as Down Syndrome and miscarriages, and are the hallmarks of almost all types of cancers. The centromere, a complex of DNA and proteins, is central to the chromosome inheritance process and contributes to formation of the kinetochore, heterochromatin and sister chromatid cohesion. Defects in centromere functions lead to aneuploidy or tumor formation in yeast, flies and mice. CENP-A, a conserved H3-1ike histone that replaces H3 in centromeric nucleosomes, is the structural and functional foundation of the kinetochore and adjacent centromeric region. We have shown that kinetochore chromatin is uniquely arranged as interspersed domains of CENP-A and H3 nucleosomes that promote a specialized cylindrical structure on metaphase chromosomes. This special structure is formed on divergent DNA sequences, and it is not known how centromeric chromatin is established and maintained, nor the structural and functional aspects if it is altered. The goal of this proposal is to apply an integrative, dual-system approach, using novel reagents and techniques that I have developed in my former lab, to test key organizational and functional aspects of centromeric chromatin in Drosophila and humans. We propose to investigate the roles of genomic structure and chromatin organization and dynamics in assembly and regulation of CENP-A chromatin, centromeric domains, and metaphase kinetochore structure.