Molecular Mechanisms in the Arabidopsis Circadian Clock

拟南芥昼夜节律钟的分子机制

• 批准号: 8448594
• 负责人: STEVE A KAY
• 金额: $ 38.74万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8448594
• 关键词: Affect; Animal Model; Animals; Arabidopsis; Area; Behavioral; Binding; Biochemical; Biochemistry; Biological Clocks; Biology; Cells; Circadian Rhythms; Complement; Complex; Computer Architectures; Computing Methodologies; Cues; DNA Binding; Data; Disease; Elements; Ensure; Environment; Eukaryotic Cell; Family; Feedback; Financial compensation; Flowers; Gene Family; Genes; Genetic; Genomics; Goals; Grant; Growth; Health; High temperature of physical object; Homologous Gene; Hour; Human; Investigation; Laboratories; Libraries; Light; Link; Mediating; Mining; Modeling; Molecular; Molecular Target; Organism; Output; Pathway interactions; Perception; Photosynthesis; Physiological; Physiology; Plants; Play; Post-Translational Regulation; Process; Property; Regulation; Regulator Genes; Research; Resource Allocation; Role; Sensory; Specificity; Stimulus; System; Temperature; Time; Translating; Vascular Plant; Work; base; circadian pacemaker; cold temperature; feeding; fitness; functional genomics; genome-wide; human disease; insight; member; novel strategies; positional cloning; programs; promoter; research study; response; screening; tool; transcription factor

DESCRIPTION (provided by applicant): The circadian clock is an endogenous molecular oscillator with a period of approximately 24 hours that is present nearly ubiquitously in bacterial fungal, plant, and animal species. External stimuli, such as light or temperature, are entrainment cues that ensure that the circadian oscillator is in precise resonance with the local environment. Self-sustained rhythms are maintained by clock network architecture through multiple, interlocked transcriptional feedback loops and extensive post-translational regulation. The robust circadian network coordinates biochemical, physiological, and behavioral responses with environmental rhythms to optimize resource allocation and increase fitness. We propose to deploy a combination of genetics, biochemistry, functional genomics, and computational approaches to identify the components and molecular mechanisms that underlie the multilayered clock network. Areas that we will gain direct insight into through the work proposed in this grant include the fundamental sensory pathways for environmental input into the clock, circadian network dynamics, and mechanistic control of outputs. By screening a comprehensive transcription factor library with core clock promoters, we have identified putative elements that mediate the perception and transcriptional responses to temperature inputs into the clock. We will explore their roles in temperature- associated phenomenon (entrainment, gating, and compensation) in relation to the circadian oscillator. Also, recent work in the laboratory has identified biochemical properties of key transcription factors, TOC1 and LUX, which provide important advances in our understanding of their roles within the clock. We propose to further characterize the mechanistic underpinnings of their activities through biochemical and molecular approaches, as well as explore their function on a genomic level to understand their role in the control of clock outputs. Finally, while robustness in networks is partially built on redundancy of components, this redundancy hinders our ability to identify new factors and understand their function through genetic perturbations. To circumvent this obstacle, we have developed a new computational approach for identifying functional specificity in multi-gene families by mining microarray data. We propose to expand this approach on all Arabidopsis transcription factor families and validate the approach on preliminary candidates affecting the circadian network. This new tool can be broadly applied to any organism with microarray expression data to identify perturbations that can separate the function of closely related homologs or members of a multi-gene family. Continued efforts such as the work proposed here and the on-going research in our laboratory to elucidate the molecular mechanisms of the plant circadian clock will complement similar analyses in other systems, ultimately translating our understanding of circadian biology to impact the treatment of human circadian disorders.

描述（由申请人提供）：昼夜节律是一种内源性分子振荡器，其周期约为24小时，几乎存在于细菌真菌，植物和动物物种中。外部刺激（例如光或温度）是夹带提示，可确保昼夜节律振荡器与当地环境具有准确的共鸣。通过时钟网络体系结构通过多个互锁的转录回路和广泛的翻译后调节来维持自我维持的节奏。强大的昼夜节律网络协调生物化学，生理和行为反应，以环境节奏来优化资源分配并增加适应性。我们建议部署遗传学，生物化学，功能基因组学和计算方法的组合，以识别多层时钟网络构成的组件和分子机制。我们将通过本赠款中提出的工作获得直接深入了解的领域包括对时钟，昼夜节律网络动力学的环境输入的基本感官途径以及对产出的机械控制。通过用核心时钟启动子筛选全面的转录因子库，我们确定了推定的元素，这些元素介导了对时钟中温度输入的感知和转录响应。我们将探索它们在与昼夜节律振荡器有关的温度相关现象（夹带，门控和补偿）中的作用。此外，实验室的最新工作已经确定了关键转录因子TOC1和LUX的生化特性，这在我们对它们在时钟中的作用的理解提供了重要的进步。我们建议通过生化和分子方法进一步表征其活动的机械基础，并在基因组水平上探索它们的功能，以了解它们在时钟输出控制中的作用。最后，尽管网络中的鲁棒性部分建立在冗余上 组成部分，这种冗余阻碍了我们通过遗传扰动来识别新因素并理解其功能的能力。为了避免这一障碍，我们开发了一种新的计算方法，用于通过挖掘微阵列数据来识别多基因家族的功能特异性。我们建议将这种方法扩展到所有拟南芥转录因子家族上，并验证影响昼夜节律网络的初步候选者的方法。该新工具可以通过微阵列表达数据广泛地应用于任何生物体，以识别可以将密切相关的同源物或多基因家族成员功能分开的扰动。继续努力，例如这里提出的工作以及我们实验室正在进行的研究，以阐明植物昼夜节律时钟的分子机制，将补充其他系统中的类似分析，最终将我们对昼夜节律生物学的理解产生影响，以影响人类昼夜疾病的治疗。