Molecular Mechanism of Photoperiodic Time Measurement

光周期时间测量的分子机制

基本信息

批准号：
8503273
负责人：
TAKATO IMAIZUMI
金额：
$ 28.6万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-04-01 至 2017-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8503273
关键词：
Animals Arabidopsis Behavior Binding Biochemical Biochemical Genetics Blood Vessels Calendar Cells Chromatin Remodeling Factor Circadian Rhythms Developing Countries Development Environment Eukaryota Face Failure Flavins Flowers Foundations Gene Expression Gene Family Genes Genetic Genetic Transcription Genomics Goals Health Human Learning Libraries Light Mammals Measurement Measures Mental Depression Molecular Molecular Profiling Monitor Names Organism Pattern Perception Phase Photoperiod Photoreceptors Physiological Plant Leaves Plant Model Plants Play Post-Translational Regulation Proteins Recruitment Activity Recurrence Regulation Repression Reproduction Research Role Running Seasonal Affective Disorder Seasonal Variations Seasons Study models System Systems Biology Testing Time Transcription Coactivator Transcription Repressor/Corepressor Transcriptional Regulation base chromatin modification circadian pacemaker day length functional genomics genetic analysis histone modification mRNA Expression member programs public health relevance reproductive success research study response screening tool transcription factor

项目摘要

DESCRIPTION (provided by applicant): Organisms that fail to respond appropriately to seasonal change will face severe consequences related to survival and reproduction. For humans, seasonal variation in the amount of light causes Seasonal Affective Disorder (SAD), a recurrent subtype of depression. Although the molecular mechanisms underlying SAD remain elusive, it is known that photoperiodic mechanisms play a significant role in many cases of SAD. Many organisms, including humans, have evolved mechanisms to sense changes in day length (=photoperiod) and integrate seasonal change information into their development. The long-term goal of our research program is to elucidate the molecular mechanisms by which organisms measure changes in day length and adjust their behaviors and development accordingly. Although the molecular mechanisms of photoperiodism have not yet been well described in many organisms, recent advances in the study of the model plant Arabidopsis have increased our molecular understanding of photoperiodic time measurement and have influenced the study of other plant and animal species. In Arabidopsis, the core time-measurement mechanism is circadian-regulated transcription of the floral activator CONSTANS (CO) gene and light-regulated CO protein stability and activity. In this proposal, further characterization o this core mechanism will be done through biochemical, genetic, and genomic approaches. In Aim 1, newly identified transcriptional regulators of CO will be characterized. The findings will elucidate further how the circadian clock plays a role in regulating seasonal response by orchestrating different classes of transcription factors. In Aim 2, time-dependent chromatin modification of CO transcriptional regulation - a new mechanistic layer of understanding - will be studied. Our previous results indicated the involvement of the FKF1 blue-light photoreceptor in posttranslational regulation of CO protein. In Aim 3, the molecular function of FKF1-associating proteins on CO protein stability regulation will be examined. With these three Aims, the mechanisms by which plants monitor daily and seasonal differences through the circadian clock will be analyzed. The findings will impact plant research and our broader understanding of photoperiodism and circadian clocks in mammals and other systems. The types of transcriptional and posttranslational mechanisms present in Arabidopsis are likely conserved among all eukaryotes, thus these findings will contribute to our understanding of fundamental transcriptional regulation. These findings also have the potential to provide clues to the mechanisms involved in SAD. Finally, elucidating the photoperiodic flowering mechanism is important for understanding a major plant reproduction mechanism that is directly applicable to improvements in crop yield, an important contributor to human health especially in developing countries.

描述（由申请人提供）：无法对季节变化做出适当反应的生物体将面临与生存和繁殖相关的严重后果。对于人类来说，光照量的季节性变化会导致季节性情感障碍（SAD），这是抑郁症的一种复发性亚型。尽管 SAD 的分子机制仍然难以捉摸，但众所周知，光周期机制在许多 SAD 病例中发挥着重要作用。许多生物体，包括人类，已经进化出感知日长（=光周期）变化并将季节变化信息整合到其发育中的机制。我们研究计划的长期目标是阐明生物体测量日长变化并相应调整其行为和发育的分子机制。尽管许多生物体中光周期现象的分子机制尚未得到很好的描述，但模式植物拟南芥研究的最新进展增加了我们对光周期时间测量的分子理解，并影响了其他植物和动物物种的研究。在拟南芥中，核心时间测量机制是昼夜节律调节的花激活剂 CONSTANS (CO) 基因的转录以及光调节的 CO 蛋白稳定性和活性。在该提案中，将通过生化、遗传和基因组方法进一步表征这一核心机制。在目标 1 中，将表征新鉴定的 CO 转录调节因子。这些发现将进一步阐明生物钟如何通过协调不同类别的转录因子来调节季节性反应。在目标 2 中，将研究 CO 转录调控的时间依赖性染色质修饰——一个新的理解机制层。我们之前的结果表明 FKF1 蓝光感受器参与 CO 蛋白的翻译后调节。在目标 3 中，将检查 FKF1 相关蛋白对 CO 蛋白稳定性调节的分子功能。通过这三个目标，将分析植物通过生物钟监测日常和季节差异的机制。这些发现将影响植物研究以及我们对哺乳动物和其他系统的光周期和生物钟的更广泛的理解。拟南芥中存在的转录和翻译后机制的类型可能在所有真核生物中都是保守的，因此这些发现将有助于我们对基本转录调控的理解。这些发现还有可能为 SAD 的机制提供线索。最后，阐明光周期开花机制对于理解直接适用于提高作物产量的主要植物繁殖机制非常重要，作物产量是人类健康的重要贡献者，特别是在发展中国家。