Causes and Consequences of Genomic Instability at Fragile Sites

脆弱位点基因组不稳定的原因和后果

• 批准号: 8574218
• 负责人: Anne Marie Casper
• 金额: $ 33.17万
• 依托单位: EASTERN MICHIGAN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8574218
• 关键词: Abnormal Cell; Aphidicolin; Area; Cells; Chromosome Fragile Sites; Chromosomes; Copper; Copy Number Polymorphism; Copying Processes; DNA; DNA Damage; DNA Double Strand Break; DNA Polymerase I; DNA Repair; DNA biosynthesis; DNA polymerase alpha-primase; Deletion Mutation; Development; Disease; Environment; Event; Formaldehyde; Frequencies; Gene Conversion; Gene Deletion; Genes; Genetic; Genomic Instability; Hereditary Disease; Human; Inherited; Knowledge; Lead; Loss of Heterozygosity; Mental disorders; Mitosis; Mitotic; Mitotic Recombination; Modeling; Mutagenesis; Mutation; Neoplasm Metastasis; Normal Cell; Pathogenesis; Pathway interactions; Process; Proteins; Replication Origin; Replication-Associated Process; Role; Saccharomyces cerevisiae; Site; Source; Stress; Structure; System; Testing; Tetanus Helper Peptide; Variant; Work; Yeast Model System; Yeasts; biological adaptation to stress; cancer cell; cell growth; cell type; daughter cell; design; gene function; homologous recombination; human disease; irradiation; neoplastic cell; public health relevance; repaired; research study; tool; transmission process; tumor

DESCRIPTION (provided by applicant): 6. PROJECT SUMMARY Chromosomes in cancer cells contain changes that cause improper cell growth. When a cell can't correctly repair breaks in its DNA or has difficulty during the process of copying its DNA, genetic changes can result. When tumor cells with these changes divide and reproduce, they pass these genetic changes on to their daughter cells, eventually creating a metastasized tumor. Some regions of chromosomes are more prone to genetic changes than others. Many types of tumors have been shown to contain abnormalities at regions called "fragile sites." Fragile sites in human cells are normally stable, but when the process of copying DNA is slowed or stalled, these sites are hotspots for breaks. Yeast cells also contain fragile sites, and we will use the powerful genetic tools of the yeast model system to design experiments that would be technically difficult in human cells. In the first aim of this proposal, we will study the fidelity and extent of DNA replication that occurs when breaks are repaired during mitosis by homologous recombination. Abnormal cell growth in tumors is often caused by amplification or deletion of genes involved in cell growth and DNA repair. Thus, in the second aim we will study variations in copy number stimulated by breaks at a yeast fragile site, using a system that allows us to select for yeast that have lost or gained copies of genes that enable it to grow on media containing copper and formaldehyde. Because yeast fragile sites have a simpler structure than human ones, in the third aim, we will study the process of DNA replication in human fragile site sequences that are carried on yeast chromosomes. The experiments in this aim will test hypotheses about the models that have been proposed to explain why breaks form in human fragile sites. These experiments to study DNA damage at fragile sites and repair at stalled replication forks will help us understand the situations and environments that promote genetic changes in tumor cells.

描述（由申请人提供）： 6.项目总结癌细胞中的染色体包含导致细胞不正常生长的变化。当细胞不能正确修复其DNA中的断裂或在复制其DNA的过程中遇到困难时，可能会导致遗传变化。当具有这些变化的肿瘤细胞分裂和繁殖时，它们将这些遗传变化传递给它们的子细胞，最终产生转移的肿瘤。染色体的某些区域比其他区域更容易发生遗传变化。许多类型的肿瘤已被证明在称为“脆性部位”的区域存在异常。“人类细胞中的脆弱位点通常是稳定的，但当复制DNA的过程减慢或停滞时，这些位点就成为断裂的热点。酵母细胞也含有脆弱位点，我们将使用酵母模型系统的强大遗传工具来设计在人类细胞中技术上困难的实验。在这个提议的第一个目标中，我们将研究DNA复制的保真度和程度，当断裂在有丝分裂期间通过同源重组修复时发生。肿瘤中的异常细胞生长通常由参与细胞生长和DNA修复的基因的扩增或缺失引起。因此，在第二个目标中，我们将研究在酵母脆性位点的断裂刺激的拷贝数的变化，使用一个系统，使我们能够选择已经丢失或获得基因拷贝的酵母，使其能够在含有铜和甲醛的培养基上生长。由于酵母脆性位点的结构比人类的结构简单，因此在第三个目标中，我们将研究酵母染色体上携带的人类脆性位点序列中的DNA复制过程。在这一目标的实验将测试的模型，已提出解释为什么打破人类脆弱的网站形成的假设。这些研究脆弱位点DNA损伤和停滞复制叉修复的实验将帮助我们了解促进肿瘤细胞遗传变化的情况和环境。