RUI: Analysis of Chromatin-level Mechanisms Regulating Genomic Imprinting in Mouse

哺乳动物中的大多数基因都是从母亲和父亲那里继承的副本中表达的，但也有一小部分基因只在这两个副本中的一个副本中表达；这些基因被称为印迹基因。该项目旨在研究最终允许这些印记基因的一个副本表达，而另一个副本保持沉默或不起作用的机制。了解这些基因的调控很重要，因为如果印记基因的表达失调，那么哺乳动物生长和发育的正常模式就会受到干扰，比如当两个拷贝都表达或两个拷贝都不表达时。这些研究将在布林莫尔学院进行，这是一所女子本科院校，将为一群不同的本科生提供更好的教育环境，让他们有机会使用当前的方法推进科学探索，最终为这些本科生培养成为下一代研究科学家。印记基因只表达于两个父母遗传的等位基因中的一个。印记基因的单等位基因表达与受精时传递给后代的母系和父系等位基因上的不同DNA甲基化有关。目前尚不清楚的是，如何在受精后发育过程中进一步完善染色质结构，以保持印迹表达并建立组织特异性印迹。受精后获取印迹基因内额外位置的DNA甲基化已被提出用于这一目的，但这些次级差异甲基化区域的DNA甲基化是高度可变的。这项研究将检验所观察到的变异是由于半甲基化水平增加和/或5-羟甲基胞嘧啶水平增加所致的假设。此外，这项工作将利用染色体构象捕获来识别负责组织特异性印迹的顺式调控元件，以了解这些元件如何与表观遗传因子协同工作，实现单等位基因与双等位基因的表达。总体而言，这项研究将有助于深入了解对印记基因表达至关重要的染色质结构的建立和维持机制。

Most genes in mammals are expressed from copies inherited from both the mother and the father, but a small number of genes are only expressed from one of these two copies; these are called imprinted genes. This project aims to investigate the mechanisms that ultimately allow one copy of these imprinted genes to be expressed while the other copy remains silent, or non-functional. Understanding the regulation of these genes is important because normal patterns of mammalian growth and development are perturbed if the expression of imprinted genes is dysregulated, as when both or neither copy is expressed. These studies will be conducted at Bryn Mawr College, a women's undergraduate institution, and will provide a diverse cohort of undergraduate students with an enhanced educational environment by affording them the opportunity to use current methodologies to advance scientific exploration, ultimately preparing these undergraduate women to be the next generation of research scientists.Imprinted genes are only expressed from one of the two parentally inherited alleles. Monoallelic expression of imprinted genes is associated with differential DNA methylation on the maternal and paternal alleles that are passed to offspring at fertilization. What remains unknown is how further refinement of chromatin structure is achieved during post-fertilization development in order to maintain imprinted expression and establish tissue-specific imprinting. Post-fertilization acquisition of DNA methylation at additional sites within imprinted loci has been proposed to serve this purpose, but DNA methylation at such secondary differentially methylated regions is highly variable. This research will test the hypotheses that the observed variability is due to increased levels of hemi-methylation and/or increased levels of 5-hydroxymethylcytosine. In addition, this work will identify cis-regulatory elements responsible for tissue-specific imprinting using chromosome conformation capture to understand how these elements work in concert with epigenetic factors to achieve monoallelic vs. biallelic expression. Overall, this research will lend insight into the mechanisms governing the establishment and maintenance of chromatin structure critical for imprinted gene expression.