A pdf Neuropeptide Gene Mutation and Ablation of PDF Neurons Each Cause Severe Abnormalities of Behavioral Circadian Rhythms in Drosophila

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 (LNv 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 LNv neurons as the principal circadian pacemakers controlling daily locomotion in Drosophila. They also implicate PDF as the principal circadian transmitter.

Clk post-transcriptional control denoises circadian transcription both temporally and spatially

“…PDF is expressed in eight neurons in each brain lobe 18 . Most (69 out of 70) examined ClkWT brain hemispheres had eight canonical LNvs per brain lobe (Fig.…”

“…However, a group of B150 neurons in the brain drives circadian rhythms in locomotor activity 18 . These neurons have been divided into several subgroups based on their anatomical location and expression of the core clock genes 19,20 .…”

“…These groups are small and large ventral lateral (sLNvs and lLNvs), dorsal lateral (LNds), and dorsal (DN1s, DN2s and DN3s) neurons. The neuropeptide pigment dispersing factor (PDF), which is expressed exclusively in the LNvs, is essential for normal circadian patterns of activity in light and dark and for persistent circadian rhythms in constant darkness (DD) 18 .…”

Reciprocal regulation of carbon monoxide metabolism and the circadian clock

“…24) and an insertion of an empty pUASTattB vector into the attP landing site at 51C 50 . Pdf-gal4, tim-Gal4:62, 67, 27, repo-gal4 and elav-gal4 have been described previously 24,[51][52][53] . To record period-luciferase rhythms 8.0-luc:9, XLG-luc:1 (ref.…”

Even a stopped clock tells the right time twice a day: circadian timekeeping in Drosophila

“…Three initial studies suggested the importance of the s-LN v s in driving behavioural rhythms: (1) the presence of just one s-LN v in a disconnected mutant is sufficient for a fly to display some rhythms, while flies with no s-LN v s remaining are arrhythmic [71]; (2) cry b mutants are rhythmic in DD, with the s-LN v s the only cells to show rhythms in TIM protein levels, at least in LD cycles [26]; and (3) PDF is only produced in LN v s, and Pdf null mutants become arrhythmic after 1-2 days in DD [72]thus LN v s are important for rhythms. However, the persistence of rhythms for the first 2 days in DD in Pdf mutants and in flies in which PDF cells have been ablated indicates that other cells are also required to drive normal behavioural rhythms.…”