DNA-binding and dimerization preferences of Arabidopsis homeodomain-leucine zipper transcription factors in vitro

Plant Mol Biol. 2001 Jan;45(1):63-73. doi: 10.1023/a:1006423324025.


Homeodomain-leucine zipper (HDZip) proteins constitute a large family of transcription factors apparently unique to plants. In this report we characterize the DNA-binding and dimerization preferences in vitro of class I HDZip proteins. Using gel-exclusion chromatography and in vitro protein binding assays we demonstrate that the HDZip class I protein ATHB5 forms a homodimeric complex in solution. Consistent with this finding we have demonstrated the sequence-specific interaction of ATHB5 with a 9 bp pseudopalindromic DNA sequence, CAATNATTG, composed of two half-sites overlapping at a central position, by use of a PCR-assisted binding-site selection assay and competitive EMSA experiments. A majority of other known members of HDZip class I interacted with similar DNA sequences, but differed in their preference for A/T versus G/C in the central position of the binding site. Selective heterodimerization in vitro was demonstrated between ATHB5 and different class I HDZip proteins. Heterodimer formation between class I HDZip proteins is of potential functional significance for the integration of information from different signalling pathways in the control of plant development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / genetics*
  • Bacteria / genetics
  • Base Sequence
  • Binding Sites / genetics
  • DNA / genetics
  • DNA / metabolism*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Dimerization
  • Homeodomain Proteins / chemistry
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Leucine Zippers
  • Molecular Sequence Data
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Protein Binding
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Sequence Homology, Amino Acid
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • DNA-Binding Proteins
  • HD-Zip protein, Helianthus annuus
  • Homeodomain Proteins
  • Plant Proteins
  • Recombinant Proteins
  • Transcription Factors
  • DNA