title: Circadian clock gene expression in the ovary: Effects of luteinizing hormone.
abstract: A molecular device that measures time on a daily, or circadian, scale is a nearly ubiquitous feature of eukaryotic organisms. A core group of clock genes, whose coordinated function is required for this timekeeping, is expressed both in the central clock and within numerous peripheral organs. We examined expression of clock genes in the rat ovary. Transcripts for core oscillator elements (Arntl, Clock, Per1, Per2, and Cry1) were present in the ovary as indicated by quantitative real-time RT-PCR. Rhythmic expression patterns of Arntl and Per2 transcripts and protein products were out of phase with respect to the central oscillator and in complete antiphase to each other. Expression of Arntl was significantly elevated after the LH surge on the day of proestrus. Finally, hCG treatment induced cyclic expression of both Arntl and Per2 gene products in hypophysectomized, immature rats primed with eCG. Collectively, these data suggest that the core underpinnings of the transcriptional/translational feedback loop that drives circadian rhythmicity is present in the rat ovary. Furthermore, the study identifies LH as a potential regulator of circadian clock gene rhythms in the ovary.
authors.affiliation: Department of Veterinary Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, USA.
authors.forename: Bethany N
authors.initials: BN
authors.lastname: Karman
authors.forename: Shelley A
authors.initials: SA
authors.lastname: Tischkau
mesh_terms: D056930:ARNTL Transcription Factors; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics; D018797:Cell Cycle Proteins; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D002940:Circadian Rhythm / Q000235:genetics*; D030762:Estrous Cycle / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006062:Gonadotropins / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000378:metabolism* / Q000494:pharmacology; D009687:Nuclear Proteins / Q000235:genetics; D010053:Ovary / Q000187:drug effects / Q000502:physiology*; D056950:Period Circadian Proteins; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014157:Transcription Factors / Q000235:genetics
chemical_list: D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D018797:Cell Cycle Proteins; D006063:Chorionic Gonadotropin; D006062:Gonadotropins; D007986:Luteinizing Hormone; D009687:Nuclear Proteins; D056950:Period Circadian Proteins; D011506:Proteins; D014157:Transcription Factors; C486616:Arntl2 protein, rat; C513311:Per2 protein, rat