Analysis of GT-3a identifies a distinct subgroup of trihelix DNA-binding transcription factors in Arabidopsis

FEBS Lett. 2004 Mar 26;562(1-3):147-54. doi: 10.1016/S0014-5793(04)00222-4.


Trihelix DNA-binding factors (or GT factors) bind to GT elements found in the promoters of many plant genes. Although the binding specificity and the transcriptional activity of some members (e.g. GT-1 and GT-2) have been studied, the regulatory function of this family of transcription factors remains largely unknown. In this work, we have characterised a new GT factor, namely GT-3a, and a closely related member, GT-3b. We show that (1) they can form either homo- or heterodimers but do not interact with GT-1; (2) they are predominantly expressed in floral buds and roots; (3) GT-3a cannot bind to the binding sites of GT-1 or GT-2, but binds to the cab2 and rbcS-1A gene promoters via the 5'-GTTAC sequence, which has been previously shown to be the core of the Site 1 type of GT elements. These results suggest that GT-3a and GT-3b belong to a distinct subgroup of GT factors and that each subgroup of GT factors binds to a functionally distinct type of cis-acting GT elements.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / cytology
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / classification
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Base Sequence
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Gene Expression Regulation, Plant
  • Molecular Sequence Data
  • Nuclear Proteins / classification
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Phylogeny
  • Promoter Regions, Genetic
  • Sequence Alignment
  • Transcription Factors / classification
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • Arabidopsis Proteins
  • DNA-Binding Proteins
  • GT-3a protein, Arabidopsis
  • Nuclear Proteins
  • Transcription Factors
  • rice nuclear protein GT-2