Chickens' Cry2: molecular analysis of an avian cryptochrome in retinal and pineal photoreceptors

We have identified and characterized an ortholog of the putative mammalian clock gene cryptochrome 2 (Cry2) in the chicken, Gallus doinesticus. Northern blot analysis of gCry2 mRNA indicates widespread distribution in central nervous and peripheral tissues, with very high expression in pineal and retina. In situ hybridization of chick brain and retina reveals expression in photoreceptors and in visual and circadian system structures. Expression is rhythmic; mRNA levels predominate in late subjective night. The present data suggests that gCryy2 is a candidate avian clock gene and/or photopigment and set the stage for functional studies of gCry2. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.