Transactivation properties of parsley proline-rich bZIP transcription factors

Plant J. 2000 Apr;22(1):1-8. doi: 10.1046/j.1365-313x.2000.00687.x.


Light-responsive chalcone synthase (CHS) gene activation requires LRUCHS, a light regulatory promoter unit including the MYB recognition element MRECHS and the ACGT-containing element ACECHS. ACECHS is bound by the parsley basic region/leucine zipper (bZIP) factors CPRF1 and 4. Factors containing the bZIP domain exist in animals, plants and yeast, and recognize DNA sequence-specifically after formation of homo- or heterodimers. To determine the potential role of CPRFs in the regulation of CHS promoter activity, we investigated the functions of distinct CPRF domains in a homologous co-transfection system. The proline-rich domains of CPRF1 and CPRF4 activate transcription, indicating that CPRF1 and CPRF4 have transactivating properties. Over-expression of the CPRF1 bZIP domain caused a reduction of LRUCHS-mediated light inducibility, and point mutations throughout ACECHS affected both responsiveness to UV-containing white light and transactivation by CPRF1:VP16. The data suggest that a CPRF1-containing bZIP heterodimer interacts with ACECHS in vivo. We discuss regulatory steps in light-induced CHS transcription that may be influenced by CPRF1 and/or related bZIP factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyltransferases / genetics
  • Amino Acid Sequence
  • Animals
  • Apiaceae / genetics
  • Apiaceae / metabolism
  • Apiaceae / radiation effects
  • Base Sequence
  • Binding Sites / genetics
  • DNA, Plant / genetics
  • DNA, Plant / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Genes, Plant
  • Leucine Zippers / genetics
  • Light
  • Molecular Sequence Data
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Point Mutation
  • Proline / genetics
  • Promoter Regions, Genetic
  • Sequence Homology, Amino Acid
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transcriptional Activation / radiation effects
  • Transfection


  • CPRF protein, Petroselinum crispum
  • DNA, Plant
  • DNA-Binding Proteins
  • Plant Proteins
  • Trans-Activators
  • Proline
  • Acyltransferases
  • flavanone synthetase