A recent discovery by a team of scientists, working in part through the National Science Foundation (NSF)'s Center for Biological Timing, challenges the strongly-held belief that 24-hour rhythms (biological clocks) are centrally controlled by the brain.
Using the fruit fly as a model system to study circadian rhythms, the researchers -- led by cell biologist Steve Kay of the Scripps Research Institute in San Diego, California -- sought to determine whether individual body parts would respond to changes in the light/dark cycle. In each appendage, clock genes turned on and off in unison, according to rhythms set by environmental light manipulations.
The scientists hope that understanding the location of the clock tissues and cells, as well as identifying which genes and proteins make up the biological cogs, will lead to new strategies for the treatment of disorders associated with jet lag, shift work and seasonal depression.
"These results are fundamental to understanding how the timing of cellular functions is integrated in complex organisms," says Christopher Platt, program director in NSF's neuroscience program. "This advance shows how basic research with a model system has a broad impact on fields from agriculture to human biology."
According to Kay, "Our findings confirm that body clocks run independently in many tissues outside the brain, and are reset by light, implying that cells harbor novel photoreceptors that aren't involved in vision."
The researchers borrowed some tricks from the world of bioluminescent organisms, to measure the genes that control clocks in animals. They fused the fruit flies' clock DNA to "glow" genes either from jellyfish or fireflies, to make glow-in-the-dark fruit flies.
Kay commented, "We found that all tissues we cultured from the
whole animal were glowing on and off, demonstrating that lots of clocks
are running throughout the fly, independently of
Contact: Cheryl Dybas
National Science Foundation