Transgenerational gene silencing

摘要 在不改变DNA序列的情况下，可以持续许多代的变化在许多情况下都有报道 有机体。作为回应，人类也声称存在这种可遗传的表观遗传变化 一些有压力的经历，如饥饿和心理创伤。然而，也有穷人 理解表观遗传变化在不同世代之间持续存在的机制基础 有机体。尽管在多个系统(例如，DNA)中已经确定了介导这种变化的分子 甲基化、染色质修饰、小RNA等)，仅仅是这些分子和化学物质的存在 修饰不能预测任何新引入的表观遗传学变化的持久性。最近的概念 提供对遗传的系统级理解的进展表明，监管体系结构的变化 驱动和维护可遗传的表观遗传变化。因此，关注监管架构可以揭示 解释任何可能持续多代人的变化所需的重要交互作用 调节这些相互作用的特定分子。在线虫线虫中，有多种现象 已有报道称，利用RNA介导的调节来维持基因表达的沉默 成百上千代人。因此，这些现象为分析可遗传的表观遗传学提供了机会 改变单基因分辨率以获得洞察力。除了预期的广泛适用性之外，对 调控结构，甚至一些特定的分子用来调控可遗传的表观遗传变化 线虫，如piRNAs、相分离的RNA颗粒、双链RNA导入子SID-1，以及 与RNA结合的小分子ArgAerte蛋白在许多生物体中都是保守的，包括人类。我们的预赛 结果揭示了对促进模型稳定的RNA沉默的监管架构的洞察 编码荧光蛋白的转基因和同样易患可遗传疾病的内源性基因 基因表达的表观遗传变化。这项建议的目的是：(1)分析模型基因以发现 促进跨代基因沉默的调控序列和干扰；以及(2)分析 对内源性基因的调节，以阐明已进化为控制可遗传性的调节体系 胚系内基因表达的表观遗传变化。完成这些目标将提供一个一般性的 观察任何基因的可遗传表观遗传变化，并揭示进化机制的调控架构。 这些结果将提供对遗传性疾病的更好的了解，特别是可能具有 早几代人的表观遗传起源。

Abstract Changes that can persist for many generations without altering DNA sequence have been reported in many organisms. The existence of such heritable epigenetic changes has also been claimed in humans in response to some stressful experiences such as starvation and psychological trauma. However, there is poor understanding of the mechanistic basis for the persistence of epigenetic changes across generations in any organism. Although molecules mediating such changes have been identified in multiple systems (e.g., DNA methylation, chromatin modifications, small RNAs, etc.), the mere presence of these molecules and chemical modifications do not predict the persistence of any newly introduced epigenetic change. Recent conceptual advances that provide a system-level understanding of heredity suggest that changes in regulatory architectures drive and maintain heritable epigenetic changes. Therefore, focusing on the regulatory architectures can reveal the important interactions required for explaining any change that can last for multiple generations regardless of the particular molecules that mediate these interactions. In the nematode C. elegans, multiple phenomena have been reported whereby RNA-mediated regulation is used to sustain the silencing of gene expression for hundreds of generations. These phenomena thus provide opportunities for analyzing heritable epigenetic changes at single-gene resolution to gain insights. In addition to the expected broad applicability of insights into regulatory architectures, even some of the specific molecules used to regulate heritable epigenetic changes in C. elegans such as piRNAs, phase-separated RNA granules, the double-stranded RNA importer SID-1, and small RNA-bound Argonaute proteins are conserved in many organisms, including humans. Our preliminary results have revealed insights into a regulatory architecture that promotes stable RNA silencing of a model transgene encoding a fluorescent protein and endogenous genes that are similarly susceptible to heritable epigenetic changes in gene expression. The aims of this proposal are: (1) to analyze model genes to discover the regulatory sequences and perturbations that promote transgenerational gene silencing; and (2) to analyze regulation of endogenous genes to elucidate the regulatory architectures that have evolved to control heritable epigenetic changes in gene expression within the germline. Completion of these goals will provide both a general view of heritable epigenetic changes at any gene and reveal the regulatory architecture of evolved mechanisms. These results will provide a better understanding of hereditary diseases, particularly diseases that could have an epigenetic origin in earlier generations.