GSBS Student Publications


Ectopic CRYPTOCHROME renders TIM light sensitive in the Drosophila ovary

Student Author(s)

Alejandro Murad

GSBS Program


UMMS Affiliation

Department of Neurobiology; Emery Lab; Graduate School of Biomedical Sciences, Neuroscience Program



Document Type


Medical Subject Headings

Animals; Animals, Genetically Modified; Biological Clocks; Circadian Rhythm; Drosophila Proteins; Drosophila melanogaster; Eye Proteins; Female; *Light; Nuclear Proteins; Ovarian Follicle; Receptors, G-Protein-Coupled


Neuroscience and Neurobiology


The period (per) and timeless (tim) genes play a central role in the Drosophila circadian clock mechanism. PERIOD (PER) and TIMELESS (TIM) proteins periodically accumulate in the nuclei of pace-making cells in the fly brain and many cells in peripheral organs. In contrast, TIM and PER in the ovarian follicle cells remain cytoplasmic and do not show daily oscillations in their levels. Moreover, TIM is not light sensitive in the ovary, while it is highly sensitive to this input in circadian tissues. The mechanism underlying this intriguing difference is addressed here. It is demonstrated that the circadian photoreceptor CRYPTOCHROME (CRY) is not expressed in ovarian tissues. Remarkably, ectopic cry expression in the ovary is sufficient to cause degradation of TIM after exposure to light. In addition, PER levels are reduced in response to light when CRY is present, as observed in circadian cells. Hence, CRY is the key component of the light input pathway missing in the ovary. However, the factors regulating PER and TIM levels downstream of light/cry action appear to be present in this non-circadian organ.

Rights and Permissions

Citation: J Biol Rhythms. 2006 Aug;21(4):272-8. Link to article on publisher's site

DOI of Published Version


Related Resources

Link to Article in PubMed

Journal Title

Journal of biological rhythms

PubMed ID