title: CULLIN-3 controls TIMELESS oscillations in the Drosophila circadian clock.
abstract: Eukaryotic circadian clocks rely on transcriptional feedback loops. In Drosophila, the PERIOD (PER) and TIMELESS (TIM) proteins accumulate during the night, inhibit the activity of the CLOCK (CLK)/CYCLE (CYC) transcriptional complex, and are degraded in the early morning. The control of PER and TIM oscillations largely depends on post-translational mechanisms. They involve both light-dependent and light-independent pathways that rely on the phosphorylation, ubiquitination, and proteasomal degradation of the clock proteins. SLMB, which is part of a CULLIN-1-based E3 ubiquitin ligase complex, is required for the circadian degradation of phosphorylated PER. We show here that CULLIN-3 (CUL-3) is required for the circadian control of PER and TIM oscillations. Expression of either Cul-3 RNAi or dominant negative forms of CUL-3 in the clock neurons alters locomotor behavior and dampens PER and TIM oscillations in light-dark cycles. In constant conditions, CUL-3 deregulation induces behavioral arrhythmicity and rapidly abolishes TIM cycling, with slower effects on PER. CUL-3 affects TIM accumulation more strongly in the absence of PER and forms protein complexes with hypo-phosphorylated TIM. In contrast, SLMB affects TIM more strongly in the presence of PER and preferentially associates with phosphorylated TIM. CUL-3 and SLMB show additive effects on TIM and PER, suggesting different roles for the two ubiquitination complexes on PER and TIM cycling. This work thus shows that CUL-3 is a new component of the Drosophila clock, which plays an important role in the control of TIM oscillations.
authors.affiliation: Institut de Neurobiologie Alfred Fessard, CNRS UPR3294, Gif-sur-Yvette, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Grima
authors.forename: Alexandre
authors.initials: A
authors.lastname: Dognon
authors.forename: Annie
authors.initials: A
authors.lastname: Lamouroux
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Chélot
authors.forename: François
authors.initials: F
authors.lastname: Rouyer
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D015153:Blotting, Western; D057906:Circadian Clocks; D044842:Cullin Proteins / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D008124:Locomotion; D046912:Multiprotein Complexes / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D056950:Period Circadian Proteins / Q000378:metabolism; D010766:Phosphorylation; D055550:Protein Stability; D059748:Proteolysis; D034622:RNA Interference; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D054875:Ubiquitination
chemical_list: C503647:Cul3 protein, Drosophila; D044842:Cullin Proteins; D029721:Drosophila Proteins; D046912:Multiprotein Complexes; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; D012333:RNA, Messenger; C096445:tim protein, Drosophila