Single Gene is Linked to Jet Lag and Regulates Sleep and Wake Patterns

It turns out that there may be one gene connected to jet lag. Scientists have discovered a gene that regulates sleep and wake patterns, which could give researchers some insight into the science of sleep.

Each cell in the book has a biological "clock." This is essentially an abundance of proteins that dip or rise rhythmically over a 24-hour period. There's also a "master clock" that's responsible for establishing these cyclic circadian rhythms and keeping the body's cells in sync called the suprachiasmatic nucleus (SCN). This small, densely packed region is located in the brain's hypothalamus.

Understanding this biological clock is crucial to a person's health. Since it regulates all cells to an extent, it can also impact the way a person's body reacts.

"It's possible that the severity of many dementias comes from sleep disturbances," said Satchidananda Panda, one of the researchers, in a news release. "If we can restore normal sleep, we can address half of the problem."

In order to better understand this region, the researchers disrupted the light-dark cycles in mice and compared changes in the expressions of thousands of genes in the SCN with other mouse tissues. In the end, they identified 213 gene expression changes that were unique to SCN. They then further narrowed these down to 13 that coded for molecules that turn on and off other genes. Of these, only one was suppressed in response to light, a gene called Lhx1.

"No one had ever imagined that Lhx1 might be so intricately involved in SCN function," said Shubhroz Gill, co-author of the new paper.

Lhx1 is known for its role in neural development. In fact, it's so important that mice without this gene don't survive. Yet this is the first time it's been identified as a master regulator of light-dark cycles.  

The researchers also studied a mouse version of jet lag-an eight-hour shift in their day-night cycle. This allowed them to see that mice with little or no Lhx1 readjusted much faster to the shift than normal mice. This suggested that because these neurons are less in sync with one another, they are more easily able to shift to a new schedule.

The findings reveal a bit more about day-night cycles. More specifically, it reveals possible avenues for treatment that can restore SCN and ameliorate sleep problems.

The findings are published in the journal eLife.