A genetic approach to understanding mechanisms of epigenetic perturbation by environment

描述（由申请人提供）：这项拟议研究的广泛目标是研究遗传机制在调节毒物暴露引起的表观遗传缺陷程度中的作用。了解这些机制以及它们如何影响与环境有关的疾病的易感性，有很大的潜力对人类健康和疾病的结果产生重大影响。具体而言，本研究将检查个体之间的遗传序列差异是否决定了内分泌干扰化合物（EDC）乙烯唑啉诱导的表观遗传扰动的程度和遗传性。西洛唑林是一种抗雄激素杀真菌剂，在越来越多的引起表观遗传缺陷的内分泌干扰物中名列前茅。由于这种与表观遗传变化的联系以及环境中EDCs的广泛存在，EDCs在疾病中的作用越来越受到关注。目前大多数研究集中在确定内分泌干扰物的表观遗传效应，包括受影响的基因和对基因表达的影响。迄今为止，很少有人知道在机制水平上的直接作用模式的表观遗传扰动的EDC和因素，有助于易感性和遗传性的EDC诱导的表观遗传缺陷。EDC诱导的表观遗传缺陷的遗传性突出了EDC暴露对未来几代人健康的影响可能超过最初暴露。这对EDC相关疾病的未来患病率和诊断能力具有重要意义。在这里，我们建议调查的作用，顺式的基因序列，在该网站的扰动甲基化，并在反式，该网站的扰动甲基化以外的表观遗传反应的环境作为潜在的遗传修饰剂。我们将主要分析在生殖细胞发育的关键易感窗口期间，当全基因组表观遗传重编程发生时，乙烯唑啉诱导的表观遗传缺陷。发生在生殖细胞中的表观遗传缺陷是环境诱导的表观突变的生殖系传播（遗传性）的可能来源。我们专注于在印迹H19/Igf 2基因座诱导的表观遗传缺陷。该基因座是表观遗传调控的一个很好的模型，因为它具有一致和稳定的遗传表观遗传状态，细胞间DNA甲基化水平变化很小 类型和个人;基因座处的表观遗传状态与基因表达之间的直接相关性，使得表观遗传状态的变化总是导致基因表达的变化;以及该基因座处的正常表观遗传状态的破坏与诸如生长缺陷和癌症的疾病之间的联系。此外，在H19/Igf 2基因座的表观遗传缺陷位点发现的遗传突变最近与缺陷和表现的遗传性有关 相关的人类印记紊乱在这里，我们测试的假设，遗传序列的差异起着重要的作用，内分泌干扰物引起的表观遗传缺陷的程度和遗传性。为了验证这一假设，我们将筛选在EDC诱导的甲基化缺陷的已知位点内外具有遗传序列差异的小鼠模型，以鉴定改变EDC暴露的表观遗传效应并可能导致EDC相关疾病易感性的序列。

DESCRIPTION (provided by applicant): The broad goal of this proposed research is to investigate the role of genetic mechanisms in regulating the extent of epigenetic defects caused by toxicant exposure. Understanding these mechanisms and how they influence susceptibility to diseases related to the environment has great potential to have a major impact on human health and disease outcomes. Specifically, this study will examine whether genetic sequence differences between individuals determines the extent and heritability of epigenetic perturbation induced by the endocrine disrupting compound (EDC) vinclozolin. Vinclozolin is an antiandrogenic fungicide at the top of a growing list of EDCs that cause epigenetic defects. Because of this link to epigenetic changes and widespread presence of EDCs in the environment, EDCs are under increasing scrutiny for a greater role in disease. Most current studies focus on identifying the epigenetic effects of EDCs including genes affected and effects on gene expression. To date, very little is known at the mechanistic level regarding the direct mode of action of epigenetic perturbation by EDCs and factors that contribute to susceptibility and heritability of EDC-induced epigenetic defects. Heritability of EDC-induced epigenetic defects highlights the potential for EDC exposure to affect health beyond initial exposure into future generations. This has great implications on future prevalence and diagnostic capabilities of EDC-related disease. Here, we propose to investigate the role of genetic sequences in cis, at the site of perturbed methylation, and in trans, outside of the site of perturbed methylation as potential genetic modifiers of epigenetic response to environment. We will primarily assay vinclozolin- induced epigenetic defects during the critical susceptibility window of germ cell development when genome- wide epigenetic reprogramming is occurring. Epigenetic defects occurring in germ cells are a likely source of germ line transmission (heritability) of environmentally-induced epimutations. We focus on epigenetic defects induced at the imprinted H19/Igf2 locus. This locus is an excellent model of epigenetic regulation due to its consistent and stably inherited epigenetic states with little variation in DNA methylation levels between cell types and individuals; the direct correlation between epigenetic state at the locus and gene expression such that changes in epigenetic state always result in gene expression changes; and the link between disruption of normal epigenetic states at this locus and diseases such as growth defects and cancers. Furthermore, genetic mutations found at the site of epigenetic defects at the H19/Igf2 locus were recently linked to heritability of the defects and manifestation of the associated human imprinting disorder. Here, we test the hypothesis that genetic sequence differences play an important role in the extent and heritability of epigenetic defects caused by EDCs. To test this hypothesis we will screen mouse models with genetic sequence differences within and outside of the known site of EDC-induced methylation defects to identify sequences that modify the epigenetic effects of EDC exposure and potentially contribute to susceptibility to EDC-related disease.