Uncovering the Gene Regulatory Mechanisms Governing the Aging Circadian Clock

项目总结： 生物钟是细胞功能和动态平衡的重要调节器。年龄- 人类昼夜节律系统的相关变化与神经元病理有关。 最近在果蝇和老鼠身上的证据表明，节律紊乱和 神经退化；然而，人们对其中涉及的机制知之甚少。要解决这些问题 机制，我们比较了幼龄果蝇和老年果蝇头部的昼夜转录组 RNA序列我们发现，在幼龄果蝇体内有节奏地表达的几个基因 失去骑行模式在老年果蝇身上变得生理性的低或高。我们发现了一组 基因，这些基因在幼蝇头部是低的和心律不齐的，但在 老苍蝇的头。这一组包含已知的应激反应基因，这些基因在 幼蝇对氧化应激或缺氧的反应。根据我们的初步数据，我们 假设时钟协调神经保护基因的有节奏的表达，我们 被称为晚期生命周期因子(LLC)，对老化的神经细胞的内在应激和损伤做出反应 系统。在目标1中，我们将测量核心昼夜节律转录的全基因组结合 通过ChIP-Seq因子CLK和CyC，并识别可能是 对这些监管变化负责。在目标2中，我们将测量染色质的修饰 H3K4me3和H3K27me3以及RNA聚合酶II的结合 在年轻和老年苍蝇头部的时钟，以表征年龄变化的染色质状态和 与衰老相关的转录变化。在目标3中，我们将测量microRNA的表达 在幼龄和老年果蝇中，全天候地识别年龄改变的microRNA调节事件 可能导致转录后节律性基因表达的变化。拟议中的工作 应该揭示时钟控制的通路，保护大脑免受与年龄相关的损伤。给定 生物钟和衰老生物学的保守分子基础，我们预计这些途径将 在人类身上也有作用。 好了！

PROJECT SUMMARY: Circadian clocks are important regulators of cellular functions and homeostasis. Age- related alterations in the human circadian system are implicated in neuronal pathologies. Recent evidence in fruit flies and mice suggests correlation between disrupted rhythms and neurodegeneration; however, very little is known about mechanisms involved. To address these mechanisms, we compared circadian transcriptome in heads of young and old Drosophila using RNA-seq. We found that several genes that were expressed in young flies in a rhythmic fashion lose cycling pattern to become constitutively low or high in old flies. We uncovered a group of genes, which were low and arrhythmic in heads of young flies but became strongly rhythmic in heads of old flies. This group contains known stress-responsive genes that are induced in young flies in response to oxidative stress or hypoxia. Based on our preliminary data, we hypothesize that clock orchestrates rhythmic expression of neuroprotective genes, which we termed late life cyclers (LLCs), in response to intrinsic stress and damage in the aging nervous system. In Aim 1, we will measure genome-wide binding of the core circadian transcription factors CLK and CYC through ChIP-Seq and identify age-specific binding events that could be responsible for these regulatory changes. In Aim 2, we will measure chromatin modifications H3K4me3 and H3K27me3 as well as RNA Polymerase II binding using ChIP-Seq around the clock in young and old fly heads to characterize the effect of age-altered chromatin state and transcriptional changes associated with aging. In Aim 3, we will measure microRNA expression around the clock in young and old flies, to identify age-altered microRNA regulatory events that could result in post-transcriptional changes in rhythmic gene expression. The proposed work should reveal clock-controlled pathways that protect brain from age-related damage. Given the conserved molecular basis of circadian clock and aging biology, we expect these pathways will also function in humans. !