title: Regulation of jun-B messenger RNA and AP-1 activity by light and a circadian clock.
abstract: The suprachiasmatic nuclei (SCN) of the hypothalamus comprise the primary pacemaker responsible for generation of circadian rhythms in mammals. Light stimuli that synchronize this circadian clock induce expression of the c-fos gene in rodent SCN, which suggests a possible role for Fos in circadian entrainment. Appropriate light stimuli also induce the expression of jun-B messenger RNA in the SCN of golden hamsters but only slightly elevate c-jun messenger RNA levels. In addition, light increases the amount of a protein complex in the SCN that binds specifically to sites on DNA known to mediate regulation by the AP-1 transcription factor. The photic regulation of both jun-B messenger RNA expression and AP-1 binding activity is dependent on circadian phase: only light stimuli that shift behavioral rhythms induce jun-B and AP-1 expression. Thus, light and the circadian pacemaker interact to regulate a specific set of immediate-early genes in the SCN that may participate in entrainment of the circadian clock.
authors.affiliation: Institute for Neuroscience, Northwestern University, Evanston, IL 60208.
authors.forename: J M
authors.initials: JM
authors.lastname: Kornhauser
authors.forename: D E
authors.initials: DE
authors.lastname: Nelson
authors.forename: K E
authors.initials: KE
authors.lastname: Mayo
authors.forename: J S
authors.initials: JS
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D001483:Base Sequence; D006224:Cricetinae; D005786:Gene Expression Regulation; D016762:Genes, fos / Q000502:physiology; D016758:Genes, jun / Q000502:physiology*; D008027:Light; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010507:Periodicity; D016755:Proto-Oncogene Proteins c-jun / Q000096:biosynthesis*; D015347:RNA Probes; D012333:RNA, Messenger / Q000096:biosynthesis*; D013493:Suprachiasmatic Nucleus / Q000502:physiology; D013997:Time Factors; D014158:Transcription, Genetic
chemical_list: D016755:Proto-Oncogene Proteins c-jun; D015347:RNA Probes; D012333:RNA, Messenger