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: 10217196
• 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/10217196
• 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递。染色体异常 数量（非整倍体）和染色体结构改变会导致出生缺陷、生殖异常和 癌症。着丝粒是染色体分离和基因组稳定性所需的位点。普通的 染色体通常只有一个着丝粒，但是，与出生缺陷和相关的基因组重排 癌症产生的染色体中两个着丝粒物理相连。这些双着丝粒通常不 大多数模型生物体都具有耐受性，正如芭芭拉·麦克林托克 (Barbara McClintock) 近 80 年前在玉米中最初所阐述的那样。 矛盾的是，双着丝粒染色体在普通人类群体中频繁出现，并且极其严重。 细胞分裂过程中稳定。研究人类双着丝粒染色体形成和命运的主要障碍 一直缺乏实验系统。为了解决这个长期存在的问题，我们开发了检测方法 实验性地创造双着丝粒人类染色体，在分子上反映自然发生的染色体 具有生物医学相关性。我们发现，在一些从头双着丝粒中，着丝粒失活发生 通过部分着丝粒缺失。然而，我们的许多工程双着丝粒染色体，特别是双着丝粒染色体 X 等染色体 (dicXs) 保留两个活性着丝粒并且非常稳定。这一发现似乎矛盾 麦克林托克的双中心命运模型。在这项提案中，我们将建立在我们之前对双中心人类的研究的基础上 利用诱导型 dicX 检测系统探索染色体稳定性的分子机制 维持两个活性着丝粒的 dicX。我们将重点研究三个主要领域：1）定义 双着丝粒结构（即着丝粒间距离）和着丝粒组成之间的分子联系 动粒结构； 2) 测试α卫星基因组结构和转录在双着丝粒中的作用 稳定性，以及 3) 研究导致不同着丝粒的着丝粒蛋白遗传机制 dicX 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双着丝粒的时间线上 通过利用强大的染色体工程系统来形成和稳定 双着丝粒染色体精确地模拟了人类中经常出现的染色体。这些研究也将 对于理解双着丝粒的形成和结构、完善长期建立的双着丝粒模型至关重要 稳定性，并为人类着丝粒功能的遗传提供新的分子见解。