title: Circadian clock- and phytochrome-regulated transcription is conferred by a 78 bp cis-acting domain of the Arabidopsis CAB2 promoter.
abstract: The Arabidopsis CAB2 promoter was used to define the terminal genomic targets that are subject to regulation by the circadian clock. An in vivo cab::luciferase bioluminescent marker was used to enable the assaying of the expression of chimeric constructs with unprecedented sensitivity and time resolution in living seedlings. Dissection of -322 to +1 of the CAB2 promoter has revealed several interesting features: it was demonstrated that the 323 bp fragment contains at least one strong general positive element. The positive element contains an ACGT core sequence specifically bound by a protein activity, termed CUF-1, and contributes to high level expression but is not required for phytochrome- or circadian-regulation. Moreover, a 78 bp domain was defined that confers both circadian- and phytochrome-regulation upon heterologous promoters. Conserved GATA sequences within the 78 bp regulatory domain are specifically bound by a protein factor designated CGF-1. The binding specificity of CGF-1 appears to be related to the GT-family of trihelix DNA-binding proteins. The role of these DNA-protein interactions is discussed in terms of clock- and phytochrome regulation, and their relevance as targets for pathways defined by photomorphogenic mutants.
authors.affiliation: NSF Center for Biological Timing, University of Virginia, Charlottesville 22903.
authors.forename: S L
authors.initials: SL
authors.lastname: Anderson
authors.forename: G R
authors.initials: GR
authors.lastname: Teakle
authors.forename: S J
authors.initials: SJ
authors.lastname: Martino-Catt
authors.forename: S A
authors.initials: SA
authors.lastname: Kay
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D001665:Binding Sites; D002940:Circadian Rhythm; D016384:Consensus Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D009838:Oligodeoxyribonucleotides; D010834:Phytochrome / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D010834:Phytochrome