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

哺乳动物中的大多数基因都是从父母双方遗传的拷贝中表达的，但也有一小部分--被称为印记基因--只从两个拷贝中的一个表达。如果印记基因的表达失调，哺乳动物生长和发育的正常模式就会受到干扰。这项研究的重点是DNA甲基化，它在指导母亲与父亲的印记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，布林莫尔学院是一所女子本科院校，将为多样化的学生提供推进科学探索的机会，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。虽然DNA甲基化中稳定的父母等位基因特异性差异通过配子遗传，并调节印记基因的表达，关于在二级差异甲基化区域（DMR）获得和维持高度可变的DNA甲基化谱的知识较少，所述二级差异甲基化区域（DMR）维持个体基因座处的印记表达模式。这项研究将提供深入了解的机制，管理建立和维护表观遗传配置文件在二级DMR。将使用氧化亚硫酸氢盐方法检查5-羟甲基胞嘧啶（5 hmC）含量，以检验继发DMR的半甲基化是5 hmC富集的结果并导致甲基化丧失和模式变异性的假设。此外，在二级DMR中观察到的高水平半甲基化表明，在这些序列中维持甲基化可能是一个复杂的过程。DNA甲基转移酶1（Dnmt 1）在继发DMR中的作用将通过分析携带Dnmt 1突变的小鼠中的DNA甲基化模式来研究，该突变对全局基因组序列与印迹基因座具有不同的影响。这些实验将检验以下假设：次级DMR处甲基化的维持可能取决于配子DMR处的甲基化，并且可能需要Dnmt 3。这项研究的成果将产生更深入的了解DNA甲基化模式的收购和维护的关键印记基因expression.This奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

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.