Abstract
The mechanisms by which circadian pacemaker systems transmit timing information to control behavior are largely unknown. Here, we define two critical features of that mechanism in
Drosophila. We first describe animals mutant for the
pdf neuropeptide gene, which is expressed by most of the candidate pacemakers (LN
v neurons). Next, we describe animals in which
pdf neurons were selectively ablated. Both sets of animals produced similar behavioral phenotypes. Both sets entrained to light, but both were largely arrhythmic under constant conditions. A minority of each
pdf variant exhibited weak to moderate free-running rhythmicity. These results confirm the assignment of LN
v neurons as the principal circadian pacemakers controlling daily locomotion in
Drosophila. They also implicate PDF as the principal circadian transmitter.