Past research has indicated that in order to function well in day to day life, most people need roughly 7 to 8 hours of restful sleep per night. Some, however, seem to require quite a bit less.
According to a new study, published June 18 in the journal Current Biology, this might be down to genetics. Two genes – Taranis and Cyclin-dependent kinase 1 (originally known for their role in cell division) have been found to be of crucial importance in fly models of sleep.
“There’s a lot we don’t understand about sleep, especially when it comes to the protein machinery that initiates the process on the cellular level,” says Kyunghee Koh, Ph.D., an Assistant Professor of Neuroscience at Thomas Jefferson University’s Farber Institute for Neurosciences and a senior author on the study. “Our research elucidates a new molecular pathway and a novel brain area that play a role in controlling how long we sleep.”
In the study, Koh et. al. introduced random mutations in 3.000 Drosophila fruit flies and observed them for their sleeping habits. This helped the team to zero in on the genes involved in sleep regulation.
Having identified a mutant line that exhibited significantly shorter sleep cycles than the rest, Koh and her colleagues performed a series of genetic and biochemical tests, which showed that these flies had an atypical variation of the Taranis gene.
Normally, Taranis binds with a known sleep regulator protein called Cyclin A to suppress Cdk1, whose function is to inhibit sleep and promote wakefulness. Genetic damage to the gene causes it to become faulty and incapable of carrying out its function, which leads to the flies getting only around 25% of their required 12 hours of sleep every night.
Previous studies had found that Cyclin A is expressed in a part of the brain that corresponds with the human hypothalamus – one of the sleep centres in the human brain. “We think this may be an arousal centre in the fly brain that Taranis helps inhibit during sleep,” noted Koh.
Even though Taranis has a human cousin, called the Trip-Br family of transcriptional regulators, it is not yet clear whether a similar system is at play in humans.
“We don’t know yet whether these genes have a role in sleep in mammals or humans, but our hope is that somehow these genes we find in flies may have similar roles in people, and might ultimately give us some novel drug targets to help us sleep better,” said Koh.
The next step for the team will be to investigate the cues that turn Taranis on and figure out which proteins the Cdk1 acts on to prevent sleep.