Origin firing at repetitive sequences and genome replication

重复序列和基因组复制的起源

• 批准号: 9008959
• 负责人: Antonio Bedalov
• 金额: $ 47.23万
• 依托单位: FRED HUTCHINSON CANCER RESEARCH CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9008959
• 关键词: Address; Affect; Age; Aging; Biological Assay; Biological Phenomena; Caloric Restriction; Cell Aging; Cell Cycle; Cells; Chromatin; Chromosome Structures; Complex; DNA; DNA biosynthesis; Data; Elements; Enzymes; Event; G1 Phase; Genes; Genetic; Genetic Polymorphism; Genetic Transcription; Genome; Genome Stability; Genomic Instability; Genomics; Genotype; Health; Heterochromatin; Histone Deacetylase; Human; Human Genome; Lead; Licensing; Light; Location; Longevity; Malignant Neoplasms; Methods; Modeling; Molecular; Monitor; Mothers; Mutation; Nature; Nucleosomes; Nucleotides; Nutritional; Nutritional status; Pathway interactions; Peptide Initiation Factors; Phase; Plasmids; Positioning Attribute; Proteins; Recruitment Activity; Repetitive Sequence; Replication Initiation; Replication Origin; Repression; Resolution; Resources; Rest; Ribosomal DNA; Role; Saccharomyces cerevisiae; Saccharomycetales; Shapes; Specificity; System; Tandem Repeat Sequences; Temperature; Testing; Time; Trans-Activators; Variant; Work; Xenopus; Yeasts; carcinogenesis; chromatin remodeling; deep sequencing; environmental change; epigenome; epigenomics; gel electrophoresis; genome-wide; insight; research study; tool

DESCRIPTION (provided by applicant) Over half of the human genome is comprised of repetitive DNA organized as gene-poor, late replicating, transcriptionally silent heterochromatin. Recent studies suggest that there is a widespread opening of chromatin at repeated regions during carcinogenesis and aging. Given the total amount of repetitive DNA and the tendency of sequences in open chromatin to more readily serve as replication origins, these chromatin changes could significantly perturb global genome replication by outcompeting other regions of the genome for limiting replication factors. Indeed, our data from budding yeast suggest that increasing the efficiency of origin firing at repetitive sequences impairs DNA replication across the genome. In this proposal we use Saccharomyces cerevisiae to test our model that nucleosome re-positioning promotes the recruitment of initiation factors to replication origins in repetitive sequences and furthermore, that activation of origins in these repetitive sequences compromises the replication and stability of unique portions of the genome. S. cerevisiae is an excellent system in which to perform these tests: the major repetitive sequence, the ribosomal DNA (rDNA) is composed of homogenous tandem repeats (150 copies), each containing a potential origin of replication whose function is sensitive to chromatin context. Moreover, the sequence specificity of yeast origins creates uniform and predictable positioning of replication initiation factors and nucleosomes in their vicinity, greatly facilitating application and interpretation of a deep sequencing method for epigenomic profiling that we have developed. Our results will provide insights into the mechanisms by which chromatin and nucleosome positioning modulate replication origins at repetitive sequences and will shed light on the largely unexplored phenomenon of intra-genomic competition for replication resources as a mechanism that shapes global replication.

描述（由申请人提供） 超过一半的人类基因组由重复 DNA 组成，这些重复 DNA 被组织为基因贫乏、复制晚期、转录沉默的异染色质。鉴于重复 DNA 的总量，最近的研究表明，在致癌和衰老过程中，染色质的重复区域存在广泛的开放。以及开放染色质中的序列更容易充当复制起点的趋势，这些染色质变化可能会通过竞争限制复制因子的基因组其他区域来显着扰乱全局基因组复制。事实上，我们来自芽殖酵母的数据。表明增加重复序列的起始点激发效率会损害整个基因组中的 DNA 复制。在本提案中，我们使用酿酒酵母来测试我们的模型，即核小体重新定位会促进重复序列中复制起始点的起始因子的募集。这些重复序列中起源的激活会损害基因组独特部分的复制和稳定性。酿酒酵母是执行这些测试的绝佳系统：主要重复序列，核糖体DNA。 (rDNA) 由同质串联重复序列 (150) 组成，每个重复序列都包含一个潜在的复制起点，其功能对染色质环境敏感。此外，酵母起点的序列特异性在其复制起始因子副本和核小体中创建了统一且可预测的定位。周围，​​极大地促进了我们开发的表观基因组分析深度测序方法的应用和解释，我们的结果将提供对染色质和核小体定位调节重复复制起点的机制的见解。序列，并将揭示基因组内复制资源竞争作为塑造全球复制的机制这一在很大程度上尚未探索的现象。