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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
- About Us
Resetting the Biological Clock
3 July 2001 7:00 pm
Researchers have discovered a new way in which the brain coordinates the body's daily rhythm. A receptor in blood vessel walls responds to a protein that helps tell an animal what time it is. By fiddling with the receptor, researchers can shift the internal clock in a mouse or in human cells.
Inside each person ticks a biological clock that sets a daily rhythm, regulating bodily processes such as blood pressure, temperature, and sleep-wake cycles. A structure in the brain called the suprachiasmatic nucleus regulates these rhythms, but molecules in other tissues may strengthen or dampen the signals sent by the brain. This control is carried out by proteins that bind DNA, turning genes on or off throughout the day.
Cardiovascular scientists Garret FitzGerald and Peter McNamara of the University of Pennsylvania weren't studying circadian clock regulation, but they discovered something unexpected while searching for proteins that interact with hormone receptors in human vascular cells. The receptors latched onto a protein called MOP4, a close relative of a protein called CLOCK that helps regulate genes related to circadian rhythms. What's more, the hormones that normally bind to the receptors appear to regulate how tightly MOP4 clings to the receptor--when the hormones are present, MOP4 sticks to the receptor about 15 times more tightly.
Intrigued, FitzGerald and his colleagues tested whether the receptor and MOP4 could bind to DNA. They discovered that MOP4 binds to DNA better without the receptor and hormones. When they injected mice with a substance that ties up the hormones, they shifted the animals' internal clock by about 4 hours--the same effect they observed in human blood vessel cells grown in the lab.
"It's a very provocative paper," says neurobiologist Steven Reppert of the University of Massachusetts Medical School in Worcester. The finding may help identify novel ways to reset the central clock in the brain, perhaps leading to better remedies for jet lag.