RUI: Mechanisms that influence DNA methylation maintenance at imprinted genes in mouse

RUI：影响小鼠印迹基因 DNA 甲基化维持的机制

• 批准号: 2024342
• 负责人: Tamara Davis
• 金额: $ 38.64万
• 依托单位: Bryn Mawr College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2024342&HistoricalAwards=false
• 关键词: RUI; Mechanisms; influence; DNA; methylation

The majority of genes in mammals are expressed from copies inherited from both parents, but a small number – called imprinted genes – are only expressed from one of the two copies. Normal patterns of mammalian growth and development are perturbed if the expression of imprinted genes is dysregulated. This research focuses on DNA methylation, which plays a leading role in directing differential expression of the mother’s vs. the father’s copy of imprinted genes. This project will examine the mechanisms responsible for maintenance of DNA methylation at imprinted genes, in order to better understand how distribution of this DNA modification on the two parental copies results in different expression patterns. These studies will be conducted at Bryn Mawr College, a women’s undergraduate institution, and will provide a diverse cohort of students the opportunity to advance scientific exploration, expand their data science literacy and prepare them to be the next generation of research scientists.While stable parental allele-specific differences in DNA methylation are inherited via gametes and modulate the expression of imprinted genes, less is known about the acquisition and maintenance of highly variable DNA methylation profiles at secondary differentially methylated regions (DMRs) that maintain imprinted expression patterns at individual loci. This research will provide insight into the mechanisms that govern establishment and maintenance of epigenetic profiles at secondary DMRs. An oxidative bisulfite approach will be used to examine 5- hydroxymethylcytosine (5hmC) content to test the hypothesis that hemimethylation at secondary DMRs is a consequence of 5hmC enrichment and leads to loss of methylation and pattern variability. Furthermore, the high level of hemimethylation observed at secondary DMRs suggests that maintenance of methylation at these sequences may be a complex process. The role of DNA methyltransferase 1 (Dnmt1) at secondary DMRs will be investigated by analysis of DNA methylation patterns in mice bearing a Dnmt1 mutation that has different effects at global genomic sequences vs. imprinted loci. The experiments will test the hypothesis that maintenance of methylation at secondary DMRs may depend on methylation at gametic DMRs and may require Dnmt3. The outcomes of this research will yield greater insights into the acquisition and maintenance of DNA methylation patterns critical for imprinted gene expression.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

哺乳动物的大多数基因都是从父母双方遗传下来的拷贝中表达出来的，但是有一小部分基因——称为印迹基因——只从两个拷贝中的一个拷贝中表达出来。如果印迹基因的表达失调，哺乳动物的正常生长和发育模式就会受到干扰。这项研究的重点是DNA甲基化，它在指导母亲和父亲的印迹基因拷贝的差异表达中起着主导作用。该项目将研究负责维持印迹基因DNA甲基化的机制，以便更好地了解这种DNA修饰在两个亲本拷贝上的分布如何导致不同的表达模式。这些研究将在布林莫尔学院（Bryn Mawr College）进行，这是一所女子本科院校，将为不同的学生群体提供推进科学探索、扩大他们的数据科学素养并为他们成为下一代研究科学家做好准备的机会。虽然稳定的亲本等位基因特异性DNA甲基化差异通过配子遗传并调节印迹基因的表达，但人们对二级差异甲基化区域（DMRs）中高度可变的DNA甲基化谱的获取和维持知之甚少，而二级差异甲基化区域（DMRs）维持单个位点的印迹表达模式。这项研究将为继发性dmr表观遗传谱的建立和维持提供深入的见解。氧化亚硫酸盐方法将用于检测5-羟甲基胞嘧啶（5hmC）含量，以验证次级DMRs的半甲基化是5hmC富集的结果，并导致甲基化和模式可变性的丧失的假设。此外，在次级DMRs中观察到的高水平半甲基化表明，这些序列的甲基化维持可能是一个复杂的过程。DNA甲基转移酶1 （Dnmt1）在继发性DMRs中的作用将通过分析携带Dnmt1突变的小鼠的DNA甲基化模式来研究，Dnmt1突变对全球基因组序列和印迹位点有不同的影响。该实验将验证次级DMRs甲基化的维持可能依赖于配子DMRs的甲基化并且可能需要Dnmt3的假设。这项研究的结果将对印迹基因表达至关重要的DNA甲基化模式的获取和维持产生更大的见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。