Novel functions for Period 3 and Exo-rhodopsin in rhythmic transcription and melatonin biosynthesis within the zebrafish pineal organ.

ABSTRACT: Entrainment of circadian clocks to environmental cues such as photoperiod ensures that daily biological rhythms stay in synchronization with the Earth's rotation. The vertebrate pineal organ has a conserved role in circadian regulation as the primary source of the nocturnal hormone melatonin. In lower vertebrates, the pineal has an endogenous circadian clock as well as photoreceptive cells that regulate this clock. The zebrafish opsin protein Exo-rhodopsin (Exorh) is expressed in pineal photoreceptors and is a candidate to mediate the effects of environmental light on pineal rhythms and melatonin synthesis. We demonstrate that Exorh has an important role in regulating gene transcription within the pineal. In developing embryos that lack Exorh, expression of the exorh gene itself and of the

SUBMITTER: Pierce LX 

PROVIDER: S-EPMC2615473 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature