(Philadelphia, PA) - Researchers at the University of Pennsylvania School of Medicine have identified a new protein required for the circadian response to light in fruit flies. The discovery of this protein named JET brings investigators one step closer to understanding the process by which the body's internal clock synchronizes to light. Understanding how light affects circadian (24-hour) rhythms will likely open doors to future treatments of jetlag.

The body's 24-hour clock controls a multitude of internal functions such as periods of sleep and wakefulness, body temperature, and metabolism. Although circadian function produces a stable rhythm in the body, the biological clock will reset in response to light. The human condition known as jet lag takes place during the period when the body is attempting to resynchronize to the environmental light changes brought on by travel, namely from one time zone to another.

A mutant fruit fly that possesses jetlag-like behaviors enabled senior author Amita Sehgal, PhD, Professor of Neuroscience at Penn and a Howard Hughes Medical Institute (HHMI) Investigator, and colleagues to identify the gene and subsequent protein that aids in the response of the internal biological clock to light. The researchers report their findings in most recent issue of Science.

To test the circadian rhythm of fruit flies, Sehgal and others exposed wild type (control) and mutant flies to several light and dark settings constant darkness, constant light, and equal periods of light and darkness (a light-dark cycle). During exposure to constant light for one week, the controls developed a disrupted sleep pattern after a few days, while the mutants maintained a regular circadian rhythm. The mutant and control flies displayed no behavioral differences during their exposure to constant darkness and the light-dark cycle. However, when the fruit flies were shifted from one light-dark cycle to another, the mutan
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Contact: Karen Kreeger
karen.kreeger@uphs.upenn.edu
215-349-5658
University of Pennsylvania School of Medicine
29-Jun-2006