title: Flexible phase adjustment of circadian albumin D site-binding protein (DBP) gene expression by CRYPTOCHROME1.
abstract: The albumin D site-binding protein (DBP) governs circadian transcription of a number of hepatic detoxification and metabolic enzymes prior to the activity phase and subsequent food intake of mice. However, the behavior of mice is drastically affected by the photoperiod. Therefore, continuous adjustment of the phase of circadian Dbp expression is required in the liver. Here we describe a direct impact of CRYPTOCHROME1 (CRY1) on the phase of Dbp expression. Dbp and the nuclear receptor Rev-Erbalpha are circadian target genes of BMAL1 and CLOCK. Surprisingly, dynamic CRY1 binding to the Dbp promoter region delayed BMAL1 and CLOCK-mediated transcription of Dbp compared with Rev-Erbalpha. Extended presence of CRY1 in the nucleus enabled continuous uncoupling of the phase of Dbp from Rev-Erbalpha expression upon change from short to longer photoperiods. CRY1 thus maintained the peak of DBP accumulation close to the activity phase. In contrast, Rev-Erbalpha expression was phase-locked to the circadian oscillator and shaped by accumulation of its own gene product. Our data indicate that fine-tuning of circadian transcription in the liver is even more sophisticated than expected.
authors.affiliation: Department of Molecular Biology, University of Geneva, 1211 Geneva 4, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Stratmann
authors.forename: Frédéric
authors.initials: F
authors.lastname: Stadler
authors.forename: Filippo
authors.initials: F
authors.lastname: Tamanini
authors.forename: Gijsbertus T J
authors.initials: GT
authors.lastname: van der Horst
authors.forename: Jürgen A
authors.initials: JA
authors.lastname: Ripperger
mesh_terms: D056930:ARNTL Transcription Factors / Q000378:metabolism; D000818:Animals; D056926:CLOCK Proteins / Q000378:metabolism; D002940:Circadian Rhythm; D056931:Cryptochromes / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D008099:Liver / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D056953:Nuclear Receptor Subfamily 1, Group D, Member 1 / Q000378:metabolism; D017440:Photoperiod; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D056930:ARNTL Transcription Factors; C538961:Bmal1 protein, mouse; C538964:Cry1 protein, mouse; D056931:Cryptochromes; D004268:DNA-Binding Proteins; C498260:Dbp protein, mouse; C498262:Nr1d1 protein, mouse; D056953:Nuclear Receptor Subfamily 1, Group D, Member 1; D014157:Transcription Factors; D056926:CLOCK Proteins; C538944:Clock protein, mouse