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。异常染色体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，并且是几乎所有类型癌症的标志。着丝粒是DNA和蛋白质的复合体，在染色体遗传过程中起着重要作用，并有助于形成动粒、异染色质和姐妹染色单体的凝聚力。在酵母、苍蝇和小鼠中，着丝粒功能的缺陷会导致非整倍体或肿瘤的形成。CENP-A是一种保守的类H3组蛋白，在着丝粒核小体中取代H3，是着丝粒及其邻近区域的结构和功能基础。我们已经表明，着丝粒染色质是独特的安排作为散在的CENP-A和H3核小体，促进一个专门的圆柱形结构的中期染色体上的结构域。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，也不知道它的结构和功能方面是否被改变。本提案的目标是应用一种综合的双系统方法，使用我在以前的实验室开发的新试剂和技术，来测试果蝇和人类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组织和动态的CENP-A染色质，着丝粒结构域，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.