Functions and Mechanisms of Epigenetic Allelic Effects in the Brain

项目摘要 由于尚不清楚的原因，神经精神疾病的表型是可变的，并且通常是同一个基因 与不同的疾病有关我们对基因型和表型之间联系的有限理解， 阻碍了诊断和治疗技术的发展。NIMH战略优先解决这一问题 包括加深我们对改变基因表达的调节因子的理解， 与精神疾病相关的大脑活动关于等位基因特异性表观遗传效应知之甚少， 与杂合基因突变相互作用，影响表型变异和心理健康。的目标 本研究旨在从等位基因、蛋白质和细胞水平揭示脑内新的表观遗传效应。中 最近发表在神经元，我们发现了数千个基因，差异表达他们的母亲和 在小鼠和灵长类动物体内以发育调节的方式在RNA水平上的父系等位基因 个脑袋我们将这些现象称为差异等位基因表达效应（DAEE）。DAE不是由于 遗传变异或基因组印记，并涉及脑亚群中随机的单等位基因表达 细胞我们发现DAEE与杂合突变相互作用，导致单等位基因脑细胞的嵌合体 其在RNA水平上差异表达突变体与野生型等位基因。目前，我们不知道是否 DAEE导致蛋白质水平上的随机单等位基因表达，并涉及稳定或动态等位基因表达。 一段时间后细胞中的表达状态。此外，目前还不清楚DAEE在大脑发育过程中何时出现， 特定细胞类型是否始终受到不同基因的影响，以及DAEE是否可以与 杂合突变形成表型效应。因此，我们提出了一项探索性研究， 开始解决我们知识中的这些重要差距，并为未来的功能奠定基础。 和DAEEs在塑造心理健康方面的机制研究。目的1将确定表达谱 DAEEs在大脑中蛋白质和细胞水平上的不同功能类别的基因具有不同的功能， 表观遗传等位基因效应的发育模式，揭示了单等位基因和双等位基因的脑细胞群体， 蛋白质水平和测试个体细胞中的稳定与动态等位基因状态。目标2将确定 具有稳定随机单等位基因表达效应的候选常染色体基因， 在特定的行为和神经表型上的杂合突变。我们的研究意义重大 因为它解决了我们知识中的根本差距，并将揭示新的稳定和/或动态 表观遗传等位基因在蛋白质水平上对脑基因表达的影响。研究结果将为进一步的试验奠定基础 特定的功能模型，预计将揭示基因调控的机制，在等位基因和 大脑中的细胞水平有助于表型变异和精神疾病的风险。

PROJECT SUMMARY For reasons that are unclear, neuropsychiatric disorders are phenotypically variable and often the same gene is implicated in different disorders. Our limited understanding of the link between genotype and phenotype has stalled the development of improved diagnostics and therapeutics. An NIMH strategic priority to address this involves deepening our understanding of regulatory factors that alter gene expression and are important for brain processes relevant to mental illness. Little is known about allele-specific epigenetic effects that could interact with heterozygous genetic mutations to influence phenotypic variance and mental health. The goal of this study is to uncover novel epigenetic effects at the allele, protein and cellular level in the brain. In a recent publication in Neuron, we uncovered thousands of genes that differentially express their maternal and paternal alleles at the RNA level in vivo in a developmentally regulated manner in the mouse and primate brain. We refer to these phenomena as differential allele expression effects (DAEEs). DAEEs are not due to genetic variation or genomic imprinting and involve random monoallelic expression in subpopulations of brain cells. We found that DAEEs interact with heterozygous mutations to cause mosaics of monoallelic brain cells that differentially express mutant versus wildtype alleles at the RNA level. Currently, we do not know whether DAEEs result in random monoallelic expression at the protein level and involve stable or dynamic allelic expression states in a cell over time. Moreover, it is unclear when DAEEs arise during brain development, whether specific cell types are consistently impacted for different genes and whether DAEEs can interact with heterozygous mutations to shape phenotypic effects. Therefore, we propose an exploratory study that will begin to address these important gaps in our knowledge and set the foundations for future functional and mechanistic studies of DAEEs in shaping mental health. Aim 1 will determine the expression profiles of DAEEs at the protein and cellular level in the brain for different functional classes of genes with distinct developmental patterns of epigenetic allelic effects, revealing monoallelic and biallelic brain cell populations at the protein level and testing for stable versus dynamic allelic states in individual cells. Aim 2 will identify candidate autosomal genes with stable random monoallelic expression effects that shape the impact of heterozygous mutations on specific behavioral and neurological phenotypes. Our study is significant because it addresses fundamental gaps in our knowledge and will uncover novel stable and/or dynamic epigenetic allelic effects on brain gene expression at the protein level. The results will lay foundations to test specific functional models that are expected to reveal mechanisms by which gene regulation at the allele and cellular level in the brain contributes to phenotypic variance and risks for mental illness.