CELL BIOLOGY:
Multiple Clocks Keep Time in Fruit Fly Tissues
Elizabeth Pennisi
Neuroscientists have focused on the brain as the master timekeeper for biological rhythms, controlling everything from normal fluctuations in body temperature to midafternoon slumps. But on page 1632, researchers report new evidence indicating that fruit flies have independent clocks throughout their bodies. By harnessing recently developed techniques for imaging proteins in living cells, they tracked the production of a timekeeping protein, called PER. Previous work had shown that per, the gene that makes the protein, cycles on and off in the fruit fly brain to establish the body's daily rhythms; now this cycling appears to be widespread in fruit fly tissues. Other research has also revealed preliminary evidence for such tissue clocks in higher organisms, including mammals. These new clocks may help individual tissues tailor their protein production to the needs of the hour, while the brain clock oversees rhythms involving coordination of two or more different responses.
