Molecular path from internal clock to cells controlling activity revealed

The molecular pathway that carries time-of-day signals from the body's internal clock to ultimately guide daily behavior is like a black box, says Amita Sehgal, PhD, of the University of Pennsylvania.  Now, new research from Sehgal’s lab is taking a peek inside, describing a molecular pathway that connect the well-known clock neurons to cells governing rhythms of rest and activity in fruit flies. "Most colleagues would say that we have some understanding of how the clock works and how it is synchronized with light,” says Sehgal. “But we are just beginning to get a glimpse of how the clock drives behavior in the rest of an organism's systems." Normally, flies have a robust rhythm of being active during daylight hours and quiet during the night. Sehgal and her colleagues found that a microRNA named miR-279 acts through the JAK/STAT pathway to regulate locomotor activity rhythms through a daily cycling of proteins.