Molecular genetic analysis of the Arabidopsis circadian clock

植物利用内部生物钟，根据地球自转所施加的每日周期，在时间上协调生物化学和生理活动。这种内部时钟与日常环境周期的匹配显著有助于优化现场性能。本研究探讨了植物时钟机制的两个关键方面。首先是对温度补偿的遗传和生化分析，即时钟功能在一定温度范围内保持一致的特性。第二个是生物钟对基因表达的全局调控。突变分析已经鉴定出一种新的时钟成分AtPRMT5，它编码一种染色质修饰酶，作为基因表达的关键调节因子。具体的实验目标包括确定时钟机制本身中PRMT5活性的靶标，以及阐明PRMT5被调控的机制。生物钟整合了时间信息，协调了生物学的许多方面，包括基本代谢、生长素信号和反应，以及对生物和非生物应激的反应。深入了解生物钟机制的分子细节将有助于理解生物钟机制本身，以及生物钟的时间信息被用来调节基因序列表达和协调生化途径活动的调节网络。反过来，这将为培育时钟功能针对特定环境（如纬度）条件进行优化的作物提供信息和指导。教育工作将强调培养本科生、研究生和博士后科学家，使他们能够在复杂的尺度上轻松地工作，从个体基因的表达调节到全球基因组水平的分析。

Plants use an internal circadian clock to temporally coordinate biochemical and physiologic activities with the daily cycle imposed by the rotation of the earth on its axis. The matching of this internal clock with the daily environmental cycle contributes significantly to optimal field performance. This research investigates two key aspects of the plant clock mechanism. The first is a genetic and biochemical analysis of temperature compensation, the property by which clock function remains consistent across a range of temperatures. The second is the global regulation of gene expression by the circadian clock. Mutational analysis has identified a novel clock component, AtPRMT5, which encodes a chromatin modification enzyme that serves as a key regulator of gene expression. Specific experimental goals include the identification of targets of PRMT5 activity within the clock mechanism itself and the elucidation of the mechanism by which PRMT5 is regulated. The circadian clock integrates temporal information and coordinates many aspects of biology, including basic metabolism, auxin signaling and responses as well as responses to biotic and abiotic stress. Insights into the molecular details of the clock mechanism will inform an understanding of both the clock mechanism itself as well as of the regulatory network by which temporal information from the clock is used to regulate the expression of suites of genes and coordinate the activities of biochemical pathways. This, in turn, will inform and direct efforts to breed crops whose clock function is optimized for specific environmental (e.g., latitudinal) conditions. Educational efforts will emphasize the training of undergraduate, graduate and post-doctoral scientists able to work comfortably across scales of complexity, from the regulation of expression of individual genes through analyses at the global genomic level.