The Drosophila circadian network is a seasonal timer.
Previous work in Drosophila has defined two populations of circadian brain neurons, morning cells (M-cells) and evening cells (E-cells), both of which keep circadian time and regulate morning and evening activity, respectively. It has long been speculated that a multiple oscillator circadian network in animals underlies the behavioral and physiological pattern variability caused by seasonal fluctuations of photoperiod. We have manipulated separately the circadian photoentrainment pathway within E- and M-cells and show that E-cells process light information and function as master clocks in the presence of light. M-cells in contrast need darkness to cycle autonomously and dominate the network. The results indicate that the network switches control between these two centers as a function of photoperiod. Together with the different entraining properties of the two clock centers, the results suggest that the functional organization of the network underlies the behavioral adjustment to variations in daylength and season.
Stoleru
Dan
D
Howard Hughes Medical Institute and National Center for Behavioral Genomics, Department of Biology, Brandeis University, Waltham, MA 02454, USA.
Nawathean
Pipat
P
Fernández
María de la Paz
MP
Menet
Jerome S
JS
Ceriani
M Fernanda
MF
Rosbash
Michael
M
D000818:Animals; D001522:Behavior, Animal; D001683:Biological Clocks / Q000502:physiology*; D001921:Brain / Q000166:cytology / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D056931:Cryptochromes; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000502:physiology*; D005136:Eye Proteins / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism; D008027:Light; D009043:Motor Activity; D009474:Neurons / Q000502:physiology; D017440:Photoperiod; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D012621:Seasons
D056931:Cryptochromes; D029721:Drosophila Proteins; D005136:Eye Proteins; D043562:Receptors, G-Protein-Coupled; C119828:cry protein, Drosophila; C096445:tim protein, Drosophila; C080335:Sgg protein, Drosophila; D038362:Glycogen Synthase Kinase 3