Structural instability and DNA rearrangements in the centromere

着丝粒的结构不稳定和 DNA 重排

• 批准号: 8840617
• 负责人: SUSAN L FORSBURG
• 金额: $ 31.33万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8840617
• 关键词: Affect; Aneuploidy; Attenuated; Beryllium; Biological Models; Cells; Cellular Stress; Cellular biology; Centromere; Chromosomal Instability; Chromosomal translocation; Chromosome Fragile Sites; Chromosome Segregation; Chromosome Structures; Chromosomes; Chromosomes, Human, Pair 21; Chromosomes, Human, Pair 3; Congenital Abnormality; DNA; DNA Damage; DNA Repair Pathway; DNA biosynthesis; DNA repair protein; Data; Defect; Development; Disease; Down Syndrome; Drug Targeting; Epigenetic Process; Euchromatin; Event; Fission Yeast; Frequencies; Gene Rearrangement; Genes; Genetic; Genetic Models; Genome; Genome Stability; Genomic Instability; Goals; Health; Heterochromatin; Human; Human Development; Investigation; Lead; Left; Life; Loss of Heterozygosity; Maintenance; Malignant - descriptor; Malignant Neoplasms; Meiosis; Metabolism; Methods; Microscopy; Mitosis; Modeling; Modification; Molecular Biology; Mutation; Organism; Pathway interactions; Process; Proteins; Repetitive Sequence; Resolution; Risk Factors; Robertsonian Translocation; Role; Single-Stranded DNA; Stress; Structure; System; Techniques; Time; Work; Yeast Model System; Yeasts; chromosome mutation; expectation; genome integrity; human disease; insight; link protein; novel; prevent; repaired; response; segregation; single cell analysis

DESCRIPTION (provided by applicant): Chromosome instability (CIN) describes both disruptions of chromosome number such as aneuploidy or misegregation (nCIN) as well as disruptions of chromosome structure, such as chromosome translocations or rearrangements (sCIN). Both forms of CIN are associated with cancer. Progressive loss of genome integrity via CIN contributes to loss of heterozygosity, and can cause or exacerbate the disease. In addition to malignancy, disruptions in chromosome structure or number also contribute to defects in human development. For example, trisomy 21 causing Down syndrome can occur via chromosome mis-segregation (nCIN), but also from chromosome fusion via Robertsonian translocation(sCIN). Thus, the mechanisms that maintain chromosome structure and number are integral to human health at many levels. The centromere is essential for the normal segregation of chromosomes; thus, mutations affecting centromere function contribute to numerical CIN and aneuploidy. However, recent work suggests that the centromere is also vulnerable to chromosome rearrangements, fragmentation, and DNA damage, creating structural CIN. This also contributes to segregation defects. Importantly, the mechanisms that prevent sCIN in the centromere are largely unexplored. This proposal investigates structural instability associated with the centromere, specifically at the highly repetitive outer-repeat elements that are usually assembled into heterochromatin. It employs a tractable genetic system: the fission yeast S. pombe, which is well-established as a model for centromere function in higher cells. The project uses genetics, molecular biology, and novel cell biology methods, including live, single cell analysis and super-resolution microscopy, to examine the mechanisms that protect the centromere and preserve its integrity. The first Aim builds on extensive preliminary data to examine how the combination of replication defects and absence of heterochromatin increase the frequency of rearrangements. The second aim asks how proteins that are linked to centromere heterochromatin function in the DNA damage response either through centromere maintenance or effects on the euchromatin effects. The third Aim uses a novel four-chromosome fission yeast strain to study Robertsonian translocation. This is the first yeast model for this common chromosome rearrangement, and will examine evidence for centromere fusion and mechanisms for segregation and translocation in meiosis and mitosis. Together, these approaches will develop a strong mechanistic model for sCIN in the centromere with direct relevance to human health.

描述（由申请人提供）：染色体不稳定性（CIN）描述了染色体数目的破坏，如非整倍性或偏分离（nCIN），以及染色体结构的破坏，如染色体易位或重排（sCIN）。这两种形式的CIN都与癌症有关。通过CIN的基因组完整性的进行性丢失导致杂合性丢失，并且可以引起或加重疾病。除了恶性肿瘤，染色体结构或数量的破坏也有助于人类发育的缺陷。例如，引起唐氏综合征的21三体可以通过染色体错误分离（nCIN）发生，也可以通过罗伯逊易位（sCIN）从染色体融合发生。因此，维持染色体结构和数量的机制在许多层面上与人类健康不可分割。 着丝粒对于染色体的正常分离是必不可少的;因此，影响着丝粒功能的突变有助于数值CIN和非整倍性。然而，最近的研究表明，着丝粒也容易受到染色体重排，片段化和DNA损伤，产生结构性CIN。这也有助于偏析缺陷。重要的是，防止着丝粒中sCIN的机制在很大程度上尚未探索。 该建议调查与着丝粒相关的结构不稳定性，特别是在通常组装成异染色质的高度重复的外部重复元件。它采用了一个易于处理的遗传系统：分裂酵母S。粟酒裂殖酵母，这是一个良好建立的模型，在高等细胞中的着丝粒功能。该项目使用遗传学，分子生物学和新的细胞生物学方法，包括活单细胞分析和超分辨率显微镜，以检查保护着丝粒并保持其完整性的机制。 第一个目标建立在广泛的初步数据，以研究如何复制缺陷和异染色质的缺乏的组合增加重排的频率。第二个目的是询问与着丝粒异染色质相关的蛋白质如何通过着丝粒维持或对常染色质的影响在DNA损伤反应中起作用。第三个目的使用一种新型四染色体分裂酵母菌株来研究罗伯逊易位。这是这种常见的染色体重排的第一个酵母模型，并将研究着丝粒融合的证据和减数分裂和有丝分裂中的分离和易位机制。总之，这些方法将为着丝粒中的sCIN开发与人类健康直接相关的强有力的机制模型。