Centromere Function and Dicentric Chromosome Stability

着丝粒功能和双着丝粒染色体稳定性

• 批准号: 10016344
• 负责人: BETH A SULLIVAN
• 金额: $ 32.2万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-11 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10016344
• 关键词: Affect; Aneuploidy; Animal Model; Architecture; Area; Behavior; Binding; Biological; Biological Assay; Biological Models; Biology; Cell Cycle; Cell Death; Cell division; Cells; Centromere; Chromosomal Stability; Chromosome Segregation; Chromosome Structures; Chromosome abnormality; Chromosomes; Congenital Abnormality; Cytology; DNA Damage; Data; Diagnosis; Dicentric chromosome; Distant; Engineering; Ensure; Epigenetic Process; Event; Frequencies; Genetic; Genetic Transcription; Genome; Genome Stability; Genomic Instability; Genomics; Goals; Human; Human Chromosomes; Individual; Infertility; Investigation; Isochromosomes; Karyotype; Kinetochores; Knowledge; Label; Lead; Link; Maize; Malignant Neoplasms; Measures; Meiosis; Microtubules; Mitotic; Modeling; Modification; Molecular; Molecular Structure; Outcome; Patients; Pattern; Population; Protein Dynamics; Proteins; Publishing; Reagent; Research; Role; Satellite DNA; Series; Sister; Stress; Structure; System; Testing; Time; TimeLine; Transcript; Untranslated RNA; Work; base; chromosome movement; chromosome number abnormality; experience; human disease; insight; novel; offspring; reproductive; segregation; structural genomics; tool; transmission process; tumorigenesis

Chromosome inheritance ensures transmission of genetic and genomic information. Abnormal chromosome number (aneuploidy) and altered chromosome structure cause birth defects, reproductive abnormalities, and cancer. The centromere is the locus required for chromosome segregation and genome stability. Normal chromosomes typically have only one centromere, but, genome rearrangements associated with birth defects and cancer produce chromosomes in which two centromeres are physically linked. These dicentrics are not usually tolerated in most model organisms, as originally illustrated in maize by Barbara McClintock nearly 80 years ago. Paradoxically, dicentric chromosomes occur frequently in the general human population and are extremely stable during cell division. A major impediment in studying dicentric chromosome formation and fate in humans has been the absence of experimental systems. To circumvent this long-standing problem, we developed assays to experimentally create dicentric human chromosomes that molecularly mirror those that occur naturally and are biomedically relevant. We showed that in some of these de novo dicentrics, centromere inactivation occurred by partial centromere deletion. However, many of our engineered dicentric chromosomes, particularly dicentric X isochromosomes (dicXs), retain two active centromeres and are very stable. This finding appears to contradict McClintock's model of dicentric fate. In this proposal, we will build on our previous studies of dicentric human chromosomes by leveraging an inducible dicX assay system to explore molecular mechanisms governing stability of dicXs that maintain two active centromeres. We will focus on three major areas of investigation: 1) defining the molecular links between dicentric structure (i.e. inter-centromere distance) and centromere composition and kinetochore architecture; 2) testing the roles of alpha satellite genomic structure and transcription in dicentric stability, and 3) investigating mechanisms of centromere protein inheritance that result in varying centromere configurations on dicXs. Our work will place specific genomic and epigenetics events on the timeline of dicentric formation and stabilization by making use of a powerful chromosome engineering system that generates dicentric chromosomes that precisely model those that occur frequently in humans. These studies will also be critical for understanding dicentric formation and structure, refining long-established models of dicentric stability, and providing new molecular insights into inheritance of centromere function in humans.

染色体遗传确保遗传和基因组信息的传播。异常染色体 数字（非整倍）和染色体结构改变会导致先天缺陷，生殖异常和 癌症。丝粒是染色体分离和基因组稳定性所需的基因座。普通的 染色体通常只有一个集中粒，但与先天缺陷相关的基因组重排和 癌症产生染色体，其中有两个centromeres物理联系。这些dicentrics通常不是 在大多数模型生物体中，如近80年前的芭芭拉·麦克林托克（Barbara McClintock）最初在玉米中所示。 自相矛盾的是，二含十分之一的染色体经常发生在普通人口中，非常极端 在细胞分裂期间稳定。研究人类中的折叠染色体形成和命运的主要障碍 一直没有实验系统。为了解决这个长期存在的问题，我们开发了测定 通过实验创建二含二含染色体，以分子反映出天然发生的染色体，并且 在生物医学上相关。我们表明，在一些从头dicentrics中，发生了丝粒灭活 通过部分的Centromere删除。但是，我们的许多工程化的折叠染色体，尤其是二颗染色体 X同色体（DICXS）保留两个活性centromeres，并且非常稳定。这一发现似乎是矛盾的 McClintock的命运模型。在此提案中，我们将以我们先前对二分位人类的研究为基础 通过利用诱导DICX测定系统来探索稳定性的分子机制，染色体 维持两个活跃的中心粒的DICX。我们将重点关注调查的三个主要领域：1）定义 折叠结构（即中心间距离）和丝粒组成与 Kinetochore架构； 2）测试α卫星基因组结构和转录在二分位中的作用 稳定性和3）调查丝粒蛋白遗传的机制，从而导致着丝粒变化 DICXS上的配置。我们的工作将把特定的基因组和表观遗传学事件放在Dicentric的时间表上 通过使用强大的染色体工程系统来形成和稳定 精确地模拟那些经常发生的染色体。这些研究也将是 对于理解二位形成和结构至关重要，精炼了长期建立的模型 稳定性，并提供新的分子见解，以实现人类的丝粒功能的遗传。