Structural instability and DNA rearrangements in the centromere

着丝粒的结构不稳定和 DNA 重排

基本信息

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
项目类别：
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

项目摘要

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）描述了染色体数量的破坏，例如非整倍性或错误分离（nCIN），以及染色体结构的破坏，例如染色体易位或重排（sCIN）。两种形式的 CIN 都与癌症有关。 CIN 导致基因组完整性逐渐丧失，导致杂合性丧失，并可能导致或加剧疾病。除了恶性肿瘤之外，染色体结构或数量的破坏也会导致人类发育缺陷。例如，导致唐氏综合症的 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) 发生染色体融合。因此，维持染色体结构和数量的机制在许多层面上都是人类健康不可或缺的一部分。着丝粒对于染色体的正常分离至关重要。因此，影响着丝粒功能的突变会导致 CIN 和非整倍体的数量。然而，最近的研究表明，着丝粒也容易受到染色体重排、断裂和 DNA 损伤的影响，从而产生结构性 CIN。这也会导致偏析缺陷。重要的是，防止着丝粒发生 sCIN 的机制很大程度上尚未被探索。该提案研究了与着丝粒相关的结构不稳定性，特别是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：裂殖酵母S. pombe，它是公认的高等细胞着丝粒功能的模型。该项目利用遗传学、分子生物学和新颖的细胞生物学方法，包括活体单细胞分析和超分辨率显微镜，来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的基础上，研究复制缺陷和异染色质缺失的组合如何增加重排的频率。第二个目标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影响常染色质效应在 DNA 损伤反应中发挥作用。第三个目标使用新型四染色体裂殖酵母菌株来研究罗伯逊易位。这是这种常见染色体重排的第一个酵母模型，并将检查着丝粒融合的证据以及减数分裂和有丝分裂中分离和易位的机制。这些方法将共同开发一个与人类健康直接相关的着丝粒 sCIN 的强大机制模型。