Abstract
Photoreceptors of the Xenopus laevis retina are the site of a circadian clock. As part of a differential display screen for rhythmic gene products in this system, we have identified a photoreceptor-specific mRNA expressed in peak abundance at night. cDNA cloning revealed an open reading frame encoding a putative 388 amino acid protein that we have named 'nocturnin' (for night- factor). This protein has strong sequence similarity to the C-terminal domain of the yeast transcription factor, CCR4, as well as a leucine zipper-like dimerization motif. Nocturnin mRNA levels exhibit a high amplitude circadian rhythm and nuclear run-on analysis indicates that it is controlled by the retinal circadian clock at the level of transcription. Our observations suggest that nocturnin may function through protein-protein interaction either as a component of the circadian clock or as a downstream effector of clock function.
Original language | English (US) |
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Pages (from-to) | 14884-14888 |
Number of pages | 5 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 93 |
Issue number | 25 |
DOIs | |
State | Published - Dec 10 1996 |
ASJC Scopus subject areas
- General