title: The Xenopus clock gene is constitutively expressed in retinal photoreceptors.
abstract: Many aspects of normal retinal physiology are controlled by a retinal circadian clock. In Xenopus laevis, the photoreceptor cells within the retina contain a circadian clock that controls melatonin release. In this report we present the cloning and characterization of the Xenopus homolog of the Clock gene, known to be critical for normal circadian behavioral rhythms in the mouse. The Xenopus Clock gene is expressed primarily in photoreceptors within the eye and is expressed at constant levels throughout the day. Analysis of other tissues revealed that, as in other species, the Xenopus Clock gene is widely expressed. This characterization of the Clock gene provides a useful tool for further exploration of the role of the circadian clock in normal retinal function.
authors.affiliation: Department of Biology, NSF Center for Biological Timing, 264 Gilmer Hall, University of Virginia, Charlottesville, VA, USA.
authors.forename: H
authors.initials: H
authors.lastname: Zhu
authors.forename: S
authors.initials: S
authors.lastname: LaRue
authors.forename: A
authors.initials: A
authors.lastname: Whiteley
authors.forename: T D
authors.initials: TD
authors.lastname: Steeves
authors.forename: J S
authors.initials: JS
authors.lastname: Takahashi
authors.forename: C B
authors.initials: CB
authors.lastname: Green
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D056926:CLOCK Proteins; D002940:Circadian Rhythm / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis; D017403:In Situ Hybridization; D051379:Mice; D008969:Molecular Sequence Data; D010786:Photoreceptor Cells / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics*; D014982:Xenopus laevis
chemical_list: D018076:DNA, Complementary; D015534:Trans-Activators; D056926:CLOCK Proteins; C538944:Clock protein, mouse