title: Circadian dependency of nocturnal immediate-early protein induction in rat retina.
abstract: Daily rhythms in the mammalian retina are regulated by an endogenous circadian clock. Previously it was found that neuronal elements of the rat retina respond to light:dark (L:D) transitions with cell-specific changes in expression of the c-fos gene. Using a pan-Fos antibody to probe Western blots of rat retina, we have now shown that darkness is associated with a 60-fold increase in c-Fos protein, whereas levels of FosB and Fos-related antigens are invariant. The induction of c-Fos exhibits circadian dependency; accumulation of c-Fos protein was significantly enhanced, by a factor of 2.5-fold, when darkness onset was coincident with the established L:D transition. c-Fos exhibited only a low amplitude circadian rhythm in the absence of L:D cycles. Similar results were obtained for another immediate early gene (IEG) protein, Egr-1. These findings show that IEG induction in the rodent retina exhibits circadian clock dependency.
authors.affiliation: School of Biosciences, Cardiff University, Cardiff, UK.
authors.forename: Ann
authors.initials: A
authors.lastname: Humphries
authors.forename: David A
authors.initials: DA
authors.lastname: Carter
mesh_terms: D000818:Animals; D001483:Base Sequence; D002940:Circadian Rhythm; D017931:DNA Primers; D017874:Immediate-Early Proteins / Q000096:biosynthesis*; D051381:Rats; D012160:Retina / Q000378:metabolism* / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D017874:Immediate-Early Proteins