Establishing comprehensive and quantitative maps of DNA methylation in the develo

描述（由申请人提供）：DNA甲基化（DNAm）是基因表达表观遗传调控的重要组成部分，协调从胎儿到青春期以及可能以后的组织分化和发育。在人类大脑中，基因表达在这一重要的发育时期是非常动态的（Colantuoni 2011），大脑早期成熟阶段的失调在精神分裂症等神经发育障碍中起着核心作用（Weinberger 2011）。我们假设，遗传因素和/或环境损害导致的dna基本发育轨迹的偏离可能会干扰这些精心协调的基因表达模式。由于表观遗传机制确定的精神分裂症风险必须早于疾病的发展，并且大多数位点特异性dna变异发生在胎儿期到青年期，我们建议在“正常”个体的死后脑组织中进行全基因组亚硫酸盐测序（WGBS），范围从孕早期晚期到25岁。这种针对60个大脑样本的新一代测序方法可以测量每个基因组中每个胞嘧啶二核苷酸（包括非cpg背景）的DNAm水平，而现有的DNAm微阵列技术只能测量总cpg的一小部分的DNAm水平。这种放大的分辨率允许识别相邻胞嘧啶上的DNAm水平与发育和衰老相关的区域（差异甲基化区域，或“DMRs”）。然后，我们可以将这些DMRs与相同大脑样本上现有的RNA测序数据结合起来，以确定哪些DMRs在功能上参与调节发育中的人类大脑中的基因表达。缺乏对生命前30年DNA甲基化正常模式的了解是理解遗传变异如何与环境因素相互作用以改变疾病风险的重大障碍。这种综合方法结合了亚硫酸氢盐全基因组测序数据和RNA测序数据，确定了表观基因组对发育至关重要的区域，定义了精神分裂症中可能出错的“正常”多维模式。

DESCRIPTION (provided by applicant): DNA methylation (DNAm) is a crucial component of the epigenetic regulation of gene expression, orchestrating tissue differentiation and development from fetus to adolescence, and likely beyond. In the human brain, gene expression is extremely dynamic through this important time frame of development (Colantuoni 2011) and dysregulation of the early maturational stages of the brain plays a central role in neurodevelopmental disorders such as schizophrenia (Weinberger 2011). We hypothesize that deviations from essential DNAm developmental trajectories, either through genetic factors and/or environmental insults, could interfere with these carefully coordinated patterns of gene expression. Since schizophrenia risk established by epigenetic mechanisms must pre-date the development of the disorder, and the majority of the variability in site-specific DNAm occurs during fetal life through young adulthood, we propose whole genome bisulfite sequencing (WGBS) in post-mortem brain tissue from "normal" individuals ranging from the late first trimester through 25 years of age. This next-generation sequencing approach on 60 brain samples can measure DNAm levels at every cytosine dinucleotide (including non-CpG contexts) in each genome, whereas existing DNAm microarray technologies only measure DNAm levels at a fraction of the total CpGs. This magnified resolution permits identifying regions where DNAm levels at adjacent cytosines are associated with development and aging (differentially methylated regions, or "DMRs"). We can then integrate these DMRs with existing RNA sequencing data on the same brain samples to identify which DMRs are functionally involved in regulating gene expression in the developing human brain. The lack of knowledge about the normal patterns of DNA methylation during the first three decades of life is a significant hindrance towards understanding how genetic variation interacts with environmental factors in altering risk for illness. This integrative approach, combining whole-genome bisulfite sequencing data and RNA sequencing data, prioritizes regions of epigenome imperative to development, defining multidimensional patterns of "normal" that are likely go awry in schizophrenia.