Expression of the period clock gene within different cell types in the brain of Drosophila adults and mosaic analysis of these cells' influence on circadian behavioral rhythms

Abstract

The product of the period (per) gene of Drosophila melanogaster is continuously required for the functioning of the circadian pacemaker of locomotor activity. We have used internally marked mosaics to determine the anatomical locations at which per expression is required for adult rhythmicity, and thus where the fly's circadian pacemaker is likely located in this holometabolous insect. We first provide a detailed description of the distribution and nature of per-expressing cells in the fly's CNS. Using an antibody to the per gene product, or to that of a reporter of per expression, in conjunction with an antibody to the embryonic lethal-abnormal visual system (elav) gene product--which is used as a marker of neuronal identity--we have experimentally confirmed previously proposed assignments of per-expressing cells to the neuronal and glial classes. Thus, we found that per expression and elav immunoreactivity colocalized in large cells located in the lateral cortex of the central brain, as well as in more dorsally located cells in the posterior central brain. In contrast, we found that cells located at the margins of the cortex and the neuropil, and within the neuropil, as well as smaller cortical cells found throughout the brain's cortex, were elav negative, supporting the notion that they are glial in nature. Using internally marked mosaics, we find that the pacemaker is located in brain but is not exclusive to the eyes, the ocelli, or the optic lobes, which is consistent with previous reports obtained in this and other insects of this class. Although the pacemaker may be a paired structure, we show that the functioning of one of them is sufficient for rhythmicity. Finally, we report that glial expression is sufficient for some behavioral rhythmicity to be manifest. However, the rhythmicities of animals for which per expression was confined to glia were weak, suggesting that neuronal per expression as well may be required for normal pacemaker function.

Cellular Neurophysiology of the Rat Suprachiasmatic Nucleus: Electrical Properties, Neurotransmission, and Mechanisms of Synchronization

“…IA); peak activity occurred at 06:29 ± 0:26 h and then averaged in 1-h bins. Single-unit activity was circadian time (mean ± SE; n = 6; tights on from 00:00 to recorded by using glass micropipettes filled with 1 M NaCI 12:00 h circadian time), in agreement with other in vivo and (resistance = [30][31][32][33][34][35][36][37][38][39][40].…”

DCRY is a Drosophila photoreceptor protein implicated in light entrainment of circadian rhythm

“…DCRY may be responsible for this light-sensitivity. In Drosophila, lateral neurones in the brain have been thought to play an essential role in controlling circadian locomotor activities (Ewer et al 1992). Whether the DCRYexpressed in these neurones really acts as a light sensor for this main circadian oscillator is the next issue to be addressed.…”

Changes in multiple brain regions underlie species differences in a complex, congenital behavior

“…Although previous work in the fruit fly Drosophila melanogaster has separately examined the number of genes involved in interspecies reproductive isolation, including behavioral attributes (56,57), and the anatomical localization of sex differences in mating behavior within a species using mosaic individuals (58)(59)(60)(61)(62)(63)(64)(65)(66), this is the first study to examine the functional localization of cell groups that confer species differences in the subcomponents of a single homologous behavior.…”