title: Circadian transcription depends on limiting amounts of the transcription co-activator nejire/CBP.
abstract: The circadian clock orchestrates physiological and behavioral activities, including metabolism, neuronal activity, and cell proliferation in synchrony with the environmental cycle of day and night. Here we show that the Drosophila ortholog of the CBP/p300 family of transcription co-activators, nejire (nej), is an intrinsic component of the circadian clock that performs regulatory functions for circadian controlled transcription. Screening of overexpression mutants revealed that gain of nej function was associated with a loss of behavioral and molecular rhythms. Overexpression of NEJ suppresses the long period phenotype of a mutation in the clock gene period (per). NEJ physically interacts through two binding sites with CLOCK and the CLOCK. CYCLE (CLK.CYC) complex. Induction of CLK.CYC-dependent transcripts upon induction of nej expression from a heat-shock promoter showed that NEJ is limiting. Reduced CLK.CYC-mediated transcription in a nej hypomorphic mutant indicates an essential function of NEJ/CBP for CLK.CYC activity and a regulation of circadian transcription by availability of the co-activator. Competition for recruitment of NEJ/CBP provides a potential mechanism for cross-talk between circadian transcription and other CBP-dependent physiological processes.
authors.affiliation: Biochemie-Zentrum Heidelberg, Ruprecht-Karls Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.
authors.forename: Hsiu-Cheng
authors.initials: HC
authors.lastname: Hung
authors.forename: Christian
authors.initials: C
authors.lastname: Maurer
authors.forename: Steve A
authors.initials: SA
authors.lastname: Kay
authors.forename: Frank
authors.initials: F
authors.lastname: Weber
mesh_terms: D056930:ARNTL Transcription Factors; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D001665:Binding Sites; D056926:CLOCK Proteins; D002940:Circadian Rhythm / Q000235:genetics*; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D007150:Immunohistochemistry; D008156:Luciferases / Q000378:metabolism; D008163:Luminescent Measurements; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D056926:CLOCK Proteins; D029721:Drosophila Proteins; D008156:Luciferases; D015534:Trans-Activators; D050880:p300-CBP Transcription Factors; C112805:cyc protein, Drosophila; C524696:nej protein, Drosophila