Temperature may be a key cue for setting the biological clocks that govern the daily ebb and flow of activity in most animals and plants, Dartmouth Medical School geneticists have found.
Their work, reported in the August 7 issue of Science, advances understanding of how internal clocks keep time over the wide range of environmental conditions living things encounter.
Biological clocks are the cellular basis of the circadian rhythm, the 24-hour light-dark cycle that times behavior and metabolism for most organisms from plants to people. In humans, delayed resetting by the clock is an underlying cause of jet lag, and clock malfunction has been linked to seasonal affective disorder and various sleep and mental disorders.
DMS Researchers, Jay Dunlap, Ph.D., professor of biochemistry, Jennifer Loros, Ph.D., associate professor of biochemistry and postdoctoral fellows Yi Liu and Martha Merrow have demonstrated that temperature may be even more influential than light in regulating the clockwork components that cells use to pace themselves.
Their work offers insight into some fundamental properties common to all biological clocks: how they respond to temperature changes and adapt to control rhythm over a wide span.
Light had previously been thought to be the dominant signal in every organism. These studies suggest that this is almost certainly not the case, and that for many biologically and agriculturally important organisms temperature and temperature cycles may be the most important factor in setting the clock, Dunlap said.
Exploring the biological clock in one of the best-known model systems, the bread mold Neurospora, the researchers have built on their studies of a central cog, known as the Frequency (FRQ)
protein. When they compared levels of this protein and its related components under various light and temperature conditions, they found that temperature rather than visible light was the dominant cue for resetting t
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Contact: Hali Wickner
Hali.Wickner@Dartmouth.Edu
603-650-1520
Dartmouth Medical School
6-Aug-1998