Among the many biological functions regulated by the circadian clock is metabolism, which accelerates each morning and slows down each night. Now, researchers have pinpointed a gene that helps initiate the morning metabolism ramp up—a discovery that could provide clues for disorders such as insomnia, aging, even cancer and diabetes, according to a paper published last week in Science.
"The body is essentially a collection of clocks," co-lead researcher Satchidananda Panda of at the Salk Institute for Biological Studies, said in a press release. "We roughly knew what mechanism told the clock to wind down at night, but we didn't know what activated us again in the morning. Now that we've found it, we can explore more deeply how our biological clocks malfunction as we get older and develop chronic illness."
Researchers found that a protein JARID1 turns on the circadian circuit by forming a complex with known clock genes, CLOCK and BMAL1. The complex in turn spurs the production of PER—a protein whose expression follows a 24-hour cycle—every morning when PER levels are low. Working in human and mouse cells and in fruit flies, the researchers detailed JARID1a’s role in normal cellular and behavior cycling: cells that had abnormally low JARID1a expression failed to reach the peak PER protein production during the day—an indicator of normal circadian activity. Indeed, flies with low PER levels seemed to lose track of time, frequently napping throughout the day and night.
Researchers can now look to see if JARID1a plays a role in sleep disorders or chronic diseases, and thus serve as a possible target for novel drugs.
"So much of what it means to be healthy and youthful comes down to a good night's sleep," Panda says. "Now that we have identified JARID1a in activating our daytime cycle, we have a whole new avenue to explore why some people's circadian rhythms are off and to perhaps find new ways to help them."