Establishing comprehensive and quantitative maps of DNA methylation in the develo

描述(申请人提供)：DNA甲基化(DNaM)是基因表达的表观遗传调控的重要组成部分，协调从胎儿到青春期的组织分化和发育，甚至更远。在人脑中，基因表达在这一重要的发育时间框架内是极其动态的(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，偏离基本的dNaM发育轨迹，无论是通过遗传因素和/或环境侮辱，都可能干扰这些精心协调的基因表达模式。由于表观遗传机制建立的精神分裂症风险必须早于精神分裂症的发展，并且位置特异性dNaM的大部分变异发生在胎儿生命到青年时期，我们建议对从妊娠晚期到25岁的“正常”个人的死后脑组织进行全基因组亚硫酸盐测序(WGBS)。这种对60个大脑样本进行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dNaM水平。这种放大的分辨率允许识别相邻胞嘧啶的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DMR与同一大脑样本上现有的RNA测序数据相结合，以确定哪些DMR在功能上参与调节发育中的人脑的基因表达。缺乏对生命最初30年中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改变患病风险的重大障碍。这种综合的方法结合了全基因组亚硫酸氢盐测序数据和RNA测序数据，优先考虑了表观基因组发育所必需的区域，定义了精神分裂症中可能出错的“正常”的多维模式。

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.