Germ Cell-Mediated Epigenetic Memory of Ethanol Exposure

项目总结/摘要 该项目的长期目标是确定潜在的分子组成， 乙醇对生殖细胞影响的遗传性。生殖细胞是世代之间的桥梁， 它们的完整性对所有生物体的健康和生存能力至关重要。因此， 生殖细胞功能失调是导致不育的主要原因， 出生缺陷和婴儿死亡的原因在美国。值得注意的是，虽然有一个 乙醇对人类生殖细胞错误病因学的明确贡献，其作用机制， 特别是在生殖细胞分化的胚胎阶段，仍然是难以捉摸的。 乙醇影响的一个很大程度上未被探索的领域是对生殖细胞功能的干扰。 表观基因组这是特别重要的，因为（1）乙醇已经显示出强烈影响 不同体细胞类型的表观基因组和（2）胚胎生殖细胞容易受到 表观遗传修饰剂，因为它们经历了广泛的染色质重塑，包括 全基因组去甲基化和组蛋白复杂模式的建立 修改.不能正确调节这些组蛋白标记导致了虚假的重复 元件表达、生殖细胞死亡和不育。此外，初步证据显示， 在强大的遗传模型系统C. elegans指出，接触乙醇会导致 在生殖细胞中正常被抑制的染色质的可遗传的去沉默。 在这里，我们建议利用两个互补的生殖细胞模型，线虫C。 elegans和体外产生的小鼠生殖细胞，以阐明乙醇的分子性质 表观遗传改变我们将通过首先证明细菌的敏感性来实现这一目标。 细胞生理乙醇浓度引起的直接或祖先的曝光。我们将 然后彻底描述干细胞上乙醇暴露引起的表突变， 衍生的小鼠原始生殖细胞在其表观遗传重塑的时候。 我们希望这项研究能提供一个急需的全面检查， 表观遗传变化与早期生殖细胞对乙醇的特殊敏感性有关。

PROJECT SUMMARY/ABSTRACT The long-term goal of this project is to identify the molecular components underlying the heritability of ethanol's effect on germ cells. Germ cells are the bridge between generations and their integrity is paramount to the health and viability of all organisms. As such, the dysregulation of germ cells function significantly contributes to infertility and is also the leading cause of birth defects and infant deaths in the United States. Remarkably, although there is a clear contribution of ethanol to the etiology of human germ cell errors, its mechanisms of action, especially at embryonic stages of germ cell differentiation, have remained elusive. One largely under-explored area of ethanol's effect is the perturbation of germ cells' epigenome. This is particularly significant as (1) ethanol has been shown to strongly impact the epigenome of diverse somatic cell types and (2) embryonic germ cells are vulnerable to epigenetic-modifiers as they undergo an extensive remodeling of their chromatin which includes genome-wide demethylation and the establishment of a complex pattern of histone modifications. The failure to properly regulate these histone marks leads to spurious repetitive element expression, germ cell death and infertility. Furthermore, preliminary evidence gathered in the powerful genetic model system C. elegans indicates that exposure to ethanol leads to a heritable desilencing of normally repressed chromatin in germ cells. Here, we propose to leverage two complementary germ cell models, the nematode C. elegans and in vitro generated mouse germ cells, to elucidate the molecular nature of ethanol's epigenetic alterations. We will achieve this goal by first demonstrating the sensitivity of germ cells to physiological ethanol concentrations elicited from direct or ancestral exposure. We will then thoroughly characterize the epimutations arising from ethanol exposure on stem cell- derived mouse primordial germ cells at the time of their epigenetic remodeling. We expect this research to provide a much-needed comprehensive examination of the epigenetic changed that are correlated with a particular sensitivity of early germ cells to ethanol.