CRY, A DROSOPHILA CLOCK AND LIGHT-REGULATED CRYPTOCHROME, IS A MAJOR CONTRIBUTOR TO CIRCADIAN-RHYTHM RESETTING AND PHOTOSENSITIVITY

Light is a major environmental signal for circadian rhythms. We have i dentified and analyzed cry, a novel Drosophila cryptochrome gene. All characterized family members are directly photosensitive and include p lant blue light photoreceptors. We show that cry transcription is unde r circadian regulation, influenced by the Drosophila clock genes perio d, timeless, Clock, and cycle. We also show that cry protein levels ar e dramatically affected by light exposure. Importantly, circadian phot osensitivity is increased in a cry-overexpressing strain. These physio logical and genetic data therefore link a specific photoreceptor molec ule to circadian rhythmicity. Taken together with the data in the acco mpanying paper, we propose that CRY is a major Drosophila photorecepto r dedicated to the resetting of circadian rhythms.