The gene that governs the need for slumber when sick

Humans spend nearly one-third of their lives sleeping, yet sleep is still one of biology’s most enduring mysteries. Little is known about what genetic or molecular forces drive the need to sleep—until now. In a study of more than 12,000 lines of fruit flies, researchers from the Perelman School of Medicine have found a single gene, called nemuri, that increases the need for sleep. These findings are published in Science.

toddler asleep in bed with stuffed bunny toy

The nemuri protein fights germs with its inherent antimicrobial activity and it is secreted by cells in the brain to drive prolonged, deep sleep after an infection.

“While it’s a common notion that sleep and healing are tightly related, our study directly links sleep to the immune system and provides a potential explanation for how sleep increases during sickness,” says senior author Amita Sehgal, a professor of neuroscience and the director of Penn’s Chronobiology Program.

Without the nemuri gene, flies were more easily aroused during daily sleep, and their acute need for an increase in sleep—induced by sleep deprivation or infection—was reduced. Sleep deprivation, which increases the need for sleep, and to some extent infection, stimulated nemuri to be expressed in a small set of fly neurons nestled close to a known sleep-promoting structure in the brain. Overexpression of nemuri increased sleep in bacteria-infected flies, and led to their increased survival compared to non-infected control flies.

Read more at Penn Medicine News.