title: Modulation of BMAL/CLOCK/E-Box complex activity by a CT-rich cis-acting element.
abstract: The interaction between the BMAL1/CLOCK transcription factor and the cis-acting element known as the E-Box is a key event in the regulation of clock and clock-controlled gene expression. However, the fact that the ubiquitous E-Box element sits at the center of a presumably highly discriminating control system generates a certain level of puzzlement. Widely spread E-Boxes with a generic sequence CANNTG have been associated with expression of genes involved in a host of disparate biological processes, including the orchestration of circadian physiology. The intriguing specificity of this short DNA consensus element begs the hypothesis that its actual circadian properties might be encoded elsewhere, e.g., other factors or adjacent sequences. In a previous study, we found evidence that a short sequence in the mouse arginine vasopressin (AVP) proximal promoter has the ability to confer robust BMAL1/CLOCK responsiveness onto an adjacent E-Box. Here, we report the systematic analysis of this element. Our findings further define the determining features and sequence boundaries of this element, establish the effect of the photoperiod upon its interacting protein(s), and suggest that its cognate binding activity might be modulated by Zn2+ in a peripheral oscillator.
authors.affiliation: Unit on Temporal Gene Expression, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, United States.
authors.forename: Estela
authors.initials: E
authors.lastname: Muñoz
authors.forename: Michelle
authors.initials: M
authors.lastname: Brewer
authors.forename: Ruben
authors.initials: R
authors.lastname: Baler
mesh_terms: D016475:3T3 Cells; D056930:ARNTL Transcription Factors; D000818:Animals; D001127:Arginine Vasopressin / Q000235:genetics; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins / Q000502:physiology*; D056926:CLOCK Proteins; D002940:Circadian Rhythm; D004252:DNA Mutational Analysis; D024721:E-Box Elements / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D015534:Trans-Activators / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology; D014162:Transfection
chemical_list: D056930:ARNTL Transcription Factors; D001127:Arginine Vasopressin; D051792:Basic Helix-Loop-Helix Proteins; D056926:CLOCK Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C538961:Bmal1 protein, mouse; C538944:Clock protein, mouse