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） 超过一半的人基因组积累了重复的DNA，该DNA组织为基因罚款，后期复制，转录静音异染色质。最近的研究表明，在癌变和衰老期间，在重复区域的染色质开放。鉴于重复的DNA的总量以及开放染色质中序列更容易用作复制起源的趋势，这些染色质变化可能会通过胜过基因组的其他区域来显着扰动全局基因组复制，以限制复制因子。确实，我们来自萌芽酵母的数据表明，以重复序列的来源发射的效率增加了整个基因组的DNA复制。在这项提案中，我们使用酿酒酵母测试我们的模型，核小体重新定位促进了起始因子的募集，以复制起源于重复序列，并进一步，这些重复性链球菌中起源的激活是在这些重复性链球菌中的激活。重复（150份），每个副本都包含复制的潜在起源，其功能对染色质上下文敏感。此外，酵母起源的序列特异性在其附近创造了复制倡议因素和核小体的统一定位，对我们已经开发的表观基因组分析的深层测序方法的强烈支持和解释。我们的结果将提供有关染色质和核小体定位在重复序列中调节复制起源的机制的见解，并将阐明基因内竞争的重复竞争的意外现象，以复制资源作为一种构成全局复制的机制。