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The novel Drosophila tim(blind) mutation affects behavioral rhythms but not periodic eclosion
Corinna Wülbeck1, Gisela Szabo, Orie T Shafer
1Universität Regensburg, Institut für Zoologie, Lehrstuhl für Entwicklungsbiologie, 93040 Regensburg, Germany.
Genetics
|November 3, 2004
Summary
A new timeless mutant, tim(blind), reveals that the TIM protein influences circadian locomotor rhythms. This mutant impairs light-induced degradation and nuclear accumulation of TIM, affecting light responses and rhythm period.
Area of Science:
- Chronobiology
- Molecular biology
- Neuroscience
Background:
- Circadian clock function relies on nuclear localization of clock proteins.
- The timeless (tim) gene encodes the TIM protein, a crucial component of the circadian clock.
Purpose of the Study:
- To investigate the function of a novel long-period timeless mutant, tim(blind).
- To determine the role of TIM protein's nuclear accumulation in circadian rhythm regulation.
Main Methods:
- Generation and characterization of the tim(blind) mutant in Drosophila.
- Analysis of TIM protein phosphorylation, degradation, and nuclear localization.
- Behavioral assays measuring locomotor activity rhythms and responses to light pulses.
Main Results:
- The tim(blind) mutation results in a constitutively hypophosphorylated TIM protein resistant to light-induced degradation.
- tim(blind) flies exhibit impaired nuclear accumulation of TIM in pacemaker neurons and photoreceptor cells.
- Mutant flies display abnormal light responses and free-running locomotor rhythms with a period of approximately 26 hours.
Conclusions:
- The tim(blind) mutation affects TIM protein's nuclear export, impacting its accumulation and light sensitivity.
- TIM protein may function as a clock output factor, regulating the period of adult locomotor rhythms independently of core clock oscillations.