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A gene has been discovered which stops our body clock from resetting, paving the way for new drugs to combat jet lag.
A gene has been discovered which stops our body clock from resetting, paving the way for new drugs to combat jet lag.The gene slows our body's adaptation to new time zones, the team from the University of Oxford found, acting as a safety mechanism to prevent our internal clock from getting out of synch, a process which is linked to chronic diseases.
However, turning the gene off could prevent the symptoms of jet lag, tests on mice indicated.
Our bodies, like those of most life forms on earth, operate in rhythm with the circadian clock, a natural 24-hour cycle which tells us when to sleep or wake up.
This responds to natural light, but when we rapidly move to a different time zone, such as on a long-haul flight, it is thrown into disarray.
The circadian clock is governed by an area of the brain called the suprachiasmatic nuclei (SCN), which in turn receives information from a specialised system in the eyes which detects environmental light, according to the report in the journal Cell.
This allows the body to synchronise with the night and day cycle. However, scientists were unable to explain why it took so long for the body clock to 'reset' to different time zones — sometimes as long as a day for each hour the actual clock shifted.
Now a team from the University of Oxford has identified a gene in mice which appears to stop the body clock from adjusting too quickly.
This is because it can take some days for the brain to be convinced the new data about the night/day cycle is reliable, they say.
Dr Stuart Peirson said: "We've identified a system that actively prevents the body clock from re-adjusting.
"If you think about it, it makes sense to have a buffering mechanism in place to provide some stability to the clock. The clock needs to be sure that it is getting a reliable signal, and if the signal occurs at the same time over several days it probably has biological relevance.
"But it is this same buffering mechanism that slows down our ability to adjust to a new time zone and causes jet lag."
They studied gene expression in the SCN in mice that were exposed to light and darkness.
They identified around 100 genes that were switched on in response to light, revealing a sequence of events that act to retune the circadian clock.
Amongst these, they identified one molecule, SIK1, that terminates this response, acting as a brake to limit the effects of light on the clock.
When they blocked the activity of SIK1, the mice adjusted faster to changes in light cycle.
Dr. Russell Foster said that we were still a long way off from a jet lag cure, but added it was a step towards developing drugs for interrupted sleep cycles.
Disruptions in the circadian system have been linked to chronic diseases including cancer, diabetes, and heart disease, as well as weakened immunity to infections and impaired cognition.
More recently, researchers are uncovering that circadian disturbances are a common feature of several mental illnesses, including schizophrenia and bipolar disorder.
Dr Foster said: "We're still several years away from a cure for jet-lag but understanding the mechanisms that generate and regulate our circadian clock gives us targets to develop drugs to help bring our bodies in tune with the solar cycle.
"Such drugs could potentially have broader therapeutic value for people with mental health issues."
