Molecular genetic analysis of the Arabidopsis circadian clock

Dartmouth College, Hanover NH

Investigators

Abstract

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.