Epigenomic Modifications in Mammalian Neurogenesis

描述（由申请人提供）：本研究的目的是了解神经干/祖细胞的表观基因组修饰如何有助于控制自我更新和分化状态之间的动态平衡，这是发育生物学的一个基本问题，对提高我们对大脑发育机制的理解以及发育性或行为性大脑疾病的可能病因具有直接意义。这将通过描述大脑发育过程中神经发生过程中整体DNA和染色质状态的变化来完成。我们的方法将通过开发和验证一种新的遗传策略来分离内源性神经祖细胞。在这个遗传系统中，神经祖细胞和它们的直系神经子代通过两种报告基因的表达进行差异标记，从而允许对这两种细胞类型进行前瞻性的共分离，并提供适合比较全基因组表观遗传谱的父女细胞的内源性来源。利用这一遗传系统，我们将从发育中的小鼠大脑皮层中纯化神经祖细胞和后代，表征这两种细胞类型之间DNA甲基化和组蛋白修饰的差异模式，鉴定与修饰基因的细胞类型特异性表达模式相关的标记，并利用已建立的体内功能试验探索这些标记在皮质神经发生调节中的潜在功能。我们期望这项研究将提供神经发生过程中神经祖细胞表观遗传状态的全面图谱，识别对神经祖细胞命运规范可能至关重要的表观遗传标记，以及帮助识别可能导致发育和行为脑疾病的表观基因组病理改变。

DESCRIPTION (provided by applicant): The goal of this study is to understand how epigenomic modifications in neural stem/progenitor cells contribute to the control of a dynamic balance between the state of self-renewal and differentiation, a fundamental question of developmental biology that has a direct implication for improving our understanding of the mechanisms of brain development and the possible etiology of developmental or behavioral brain disorders. This will be done by characterizing the changes of global DNA and chromatin state during neurogenesis in brain development. Our approach will be aided by the development and validation of a novel genetic strategy for isolation of endogenous neural progenitor cells. In this genetic system, neural progenitor cells and their immediate neuronal progeny are differentially marked by the expression of two reporters, thereby allowing prospective co-isolation of these two cell types and providing an endogenous source of father- daughter cells suitable for comparative genome-wide epigenetic profiling. Using this genetic system, we will purify neural progenitor cells and progeny from the developing mouse cerebral cortex, characterize differential patterns of DNA methylation and histone modification between these two cell types, identify the marks that correlate with cell type-specific expression patterns of the modified genes, and explore the potential function of these marks in the regulation of cortical neurogenesis using established in vivo functional assays. We anticipate that this study will provide a comprehensive map of the epigenetic state of neural progenitor cells during neurogenesis, identify epigenetic marks potentially crucial for neural progenitor cell fate specification, as well as help identify pathological alterations in the epigenome which may lead to developmental and behavioral brain disorders. PUBLIC HEALTH RELEVANCE: Our proposed study on characterization of the epigenetic state of neural progenitor cells during the course of neurogenesis is expected to provide insight into how self-renewal and differentiation of neural progenitor cells are regulated, which has direct implication on future regenerative medicine and understanding of tumor development.