Dissecting how protein degradation couples the circadian clock to downstream processes

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For most living organisms, specific biological processes must happen at specific times of day. For example, in plants, photosynthesis, the process that converts light energy and carbon dioxide into sugar, must be timed to daylight hours. Many additional important processes are parsed out by a mechanism that controls daily timing called the circadian clock. A lot is known about genes and proteins that make up the circadian clock in plants; however how the circadian clock actually controls particular biological processes such as photosynthesis is not known. This proposal outlines experiments that will discover connections between the circadian clock and some of these timed biological processes. Understanding these connections will help us make crop plants that produce more energy and are resistant to changes in the environment, such as those caused by global climate change. Much is known about the transcriptional connections between the circadian clock and downstream biological processes, but far fewer non-transcriptional connections have been made. One example is the coincidence model for seasonal flowering which exemplifies a protein degradation-based mechanism for coupling the clock to seasonal flowering. In this system a circadian clock-controlled F-box protein times the degradation of a key regulator of flowering. Beyond this example, there are 32 additional circadian clock-controlled F-box proteins with little or no known biological function. To fully understand the protein degradation-based couplings between the circadian clock and downstream processes, the functions of these F-box proteins must be understood. In this proposal a strategy is defined for inverting the function of the 32 circadian clock-controlled F-box proteins to study their functions. The completion of the experiments in this proposal will provide a critical toolset and dataset to investigate protein degradation-based coupling mechanisms between the circadian clock and downstream biological processes. In addition, the proposed research will promote training and scientific interaction at various levels of scientific discovery. 1) Undergraduates, graduate students, post-doctoral researchers, and visiting scholars will be trained in plant genetics, molecular biology, and biochemistry in the laboratory; 2) A monthly plant ?showcase? will continue to bring together the plant science faculty, students, and personnel at Yale with New Haven high school and middle school students to foster interest in plant biology and STEM education with young scientists; 3) The proposed work is intended for direct application to crop species and will be a powerful tool to introduce environmental plasticity in order to respond to global environment changes; and 4) Dissemination of the work to the general public will be achieved using social media. The lab maintains a Twitter account (@GendronLab) and the presentations of the plant showcase are published as podcasts that are freely downloadable (http://greencafe.yale.edu). This is intended to increase advocacy for science with a focus on plant science.