University of Virginia Health System

The sleep/wake cycle in animals is controlled by an internal clock residing in the brain. My laboratory uses the fruit fly Drosophila melanogaster as a model to dissect the molecular basis of this phenomenon. Using genome-wide expression profiling we identified many novel clock-regulated transcripts in the Drosophila head. We are now pursuing genetic, molecular, and behavioral analyses that will allow us to determine how the extensive program of circadian transcript expression is organized into output pathways. We are also interested in the mechanisms by which light and temperature affect the sleep/wake cycle and other biological rhythms. Our studies have uncovered both clock-dependent and clock-independent responses in gene expression to light and temperature. We have, for example, found a set of genes expressed in the Drosophila eye that are regulated by light both directly, via photo-transduction, and indirectly, via the circadian clock. This coupling of photic and clock-controlled signals that we observed at the transcript level is potentially important for the solidification of light-dependent entrainment of the clock. In addition, the dual photic and circadian control of transcripts may allow light-dependent modulation of a specific set of circadian outputs, including phototransduction or synaptic function. We are currently examining these hypotheses.

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http://www.virginia.edu/biology/faculty/wijnen.htm