Circadian Clock- And Phytochrome-Regulated Transcription Is Conferred by a 78 Bp Cis-Acting Domain of the Arabidopsis CAB2 Promoter

Plant J. 1994 Oct;6(4):457-70. doi: 10.1046/j.1365-313x.1994.6040457.x.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / physiology*
  • Base Sequence
  • Binding Sites
  • Circadian Rhythm*
  • Consensus Sequence
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation, Plant*
  • Molecular Sequence Data
  • Nuclear Proteins / metabolism
  • Oligodeoxyribonucleotides
  • Phytochrome / metabolism*
  • Plant Proteins / metabolism
  • Plants, Genetically Modified
  • Promoter Regions, Genetic*
  • Recombinant Fusion Proteins / metabolism
  • Transcription, Genetic*


  • DNA-Binding Proteins
  • Nuclear Proteins
  • Oligodeoxyribonucleotides
  • Plant Proteins
  • Recombinant Fusion Proteins
  • Phytochrome