The role of H3K36 methyltransferases on non-CpG methylation patterning in the mammalian brain

项目总结： 人类遗传学研究已将自闭症和相关神经发育障碍(NDD)与脑电活动障碍联系起来 编码表观遗传因子的基因。虽然这些基因的突变可以影响不止一条导致 对于ASD来说，识别一条跨越ASD遗传原因的共同分子途径可以为深入了解 广泛适用的疗法。来自我们实验室的最新证据表明，一种神经元特有的DNA形式 甲基化是一种共同的表观遗传修饰，在ASD相关的神经发育疾病中被破坏。 尽管DNA甲基化被经典地认为只发生在CpG背景下的哺乳动物细胞中， 在DNMT3A建立的非CpG环境中，神经元独特地富含甲基化。此非CpG 甲基化主要发生在CA二核苷酸(MCA)上，对于神经元的正常发育和 功能。尽管MCA在调节神经元基因表达方面起着重要作用，但目前尚不清楚MCA是如何 MCA的格局在神经元基因组中被忠实地建立起来，以及额外的NDD是否涉及 大脑中动脉的中断。最近神经系统外的研究表明，组蛋白修饰可能 在引导DNMT3A介导的DNA甲基化过程中发挥核心作用，但尚不清楚 这些组蛋白修饰如何影响整个神经元基因组中的DNMT3A和MCA。 有趣的是，最近在ASD基因中发现了H3K36组蛋白甲基转移酶的突变 学习。此外，最近在神经系统外进行的研究表明，H3K36 甲基化招募DNMT3A并调节其活性。在这份提案中，我将确定H3K36病毒的破坏 甲基化介导的与DNMT3A的相互作用扰乱跨神经元基因组的MCA关键模式 导致大脑功能障碍。在目标1中，我将干扰与NDD相关的H3K36甲基转移酶，并测量如何 DNMT3A招募和MCA受到影响。这将定义组蛋白和DNA的潜在机制 调节神经元转录的修饰动力学和建立我们对如何调控的基本理解 大脑中动脉的破坏会导致疾病。在目标2中，我将探索H3K36二甲基酶NSD1的缺失是如何导致 通过共同的神经元染色质病理观察到的异质性临床上神经元基因的失调 ASD的证候群。我将使用基因组学方法来研究NSD1如何改变DNA甲基化 缺失会影响增强子的活性，从而在神经系统功能障碍和疾病中驱动转录失调。 这项分析将开始识别共同分子中的关键下游染色质相关因子 参与ASD多种遗传原因的途径，以提供对细胞功能结果的洞察和 广泛适用的疗法。

Project Summary: Human genetic studies have linked autism and related neurodevelopmental disorders (NDD) to disruption of genes encoding epigenetic factors. While mutations in these genes can affect more than one pathway that leads to ASD, identification of a common molecular pathway across genetic causes of ASD can provide insight into broadly applicable therapies. Recent evidence from our laboratory suggests that a neuronal-specific form of DNA methylation is a shared epigenetic modification that is disrupted in ASD-associated neurodevelopmental disease. Though DNA methylation is classically considered to only occur in mammalian cells in the CpG context, neurons are uniquely enriched for methylation in non-CpG contexts established by DNMT3A. This non-CpG methylation primarily occurs at CA dinucleotides (mCA) and is critical for proper neuronal development and function. Though mCA plays an important role in regulating neuronal gene expression, it is not known how the mCA landscape is faithfully established across the neuronal genome, and whether additional NDDs involve disruption of mCA. Recent studies outside the nervous system have suggested that histone modifications may play a central role in directing DNMT3A-mediated DNA methylation across the genome, but it is not known to how these histone modifications influence DNMT3A and mCA throughout the neuronal genome. Intriguingly, mutations in H3K36 histone methyltransferases have been recently identified in ASD gene studies. Additionally, recent studies conducted outside the nervous system have suggested that H3K36 methylation recruits DNMT3A and regulates its activity. In this proposal, I will determine how disruption of H3K36 methylation-mediated interactions with DNMT3A disturbs critical patterns of mCA across the neuronal genome to drive brain dysfunction. In Aim 1, I will disrupt NDD-relevant H3K36 methyltransferases and measure how DNMT3A recruitment and mCA are affected. This will define the mechanisms underlying histone and DNA modification dynamics on regulating neuronal transcription and building our basic understanding of how disruption of mCA drives disease. In Aim 2, I will explore how loss of H3K36 dimethylase NSD1 causes dysregulation of neuronal genes via shared neuronal chromatin pathology observed across heterogenous clinical syndromes of ASD. I will use genomic approaches to examine how altered DNA methylation as a result of NSD1 loss affects enhancer activity to drive transcriptional dysregulation in nervous system dysfunction and disease. This analysis will begin to identify key downstream chromatin associated factors across a common molecular pathway involved in multiple genetic causes of ASD to provide insight into functional cellular outcomes and broadly applicable therapies.