Central and peripheral circadian oscillators in Drosophila.
Drosophila circadian oscillators comprise interlocked period (per)/timeless (tim) and Clock (Clk) transcriptional/translational feedback loops. Within these feedback loops, CLOCK (CLK) and CYCLE (CYC) bind E-box elements to activate per and tim transcription, and we now show that at the same time CLK-CYC repress Clk by activating the transcriptional repressor vrille (vri), thus accounting for the opposite cycling phases of these transcripts and identifying vri as the negative component of the Clk-feedback-loop. The core oscillator mechanism is assumed to be the same for oscillators in different tissues. However, we have shown that CRYPTOCHROME (CRY) has a light-independent function in the oscillator that controls olfaction rhythms, suggesting that CRY may function within the oscillator mechanism itself as it does in mammals. These olfaction rhythms require the function of 'peripheral' oscillators which are distinct from the 'central' lateral neuron (LN) oscillators that mediate locomotor activity rhythms. Preliminary results show that antennal oscillator cells are sufficient and LNs are not necessary for olfaction rhythms, indicating that unlike the situation in mammals, the central oscillator has little impact on the olfaction rhythm oscillator under these conditions.
Hardin
Paul E
PE
Department of Biology and Biochemistry, University of Houston, Houston, TX 771204-5001, USA.
Krishnan
Balaji
B
Houl
Jerry H
JH
Zheng
Hao
H
Ng
Fanny S
FS
Dryer
Stuart E
SE
Glossop
Nick R J
NR
D000818:Animals; D056926:CLOCK Proteins; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology*; D056931:Cryptochromes; D004330:Drosophila / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology; D005136:Eye Proteins / Q000235:genetics / Q000502:physiology; D005246:Feedback; D017344:Genes, Insect; D008954:Models, Biological; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology; D056950:Period Circadian Proteins; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology; D012313:RNA / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
C120526:Clk protein, Drosophila; D056931:Cryptochromes; D029721:Drosophila Proteins; D005136:Eye Proteins; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; D043562:Receptors, G-Protein-Coupled; D014157:Transcription Factors; C119828:cry protein, Drosophila; C096445:tim protein, Drosophila; C108498:vri protein, Drosophila; D012313:RNA; D056926:CLOCK Proteins