STF1 is a novel TGACG-binding factor with a zinc-finger motif and a bZIP domain which heterodimerizes with GBF proteins

Plant J. 1998 Jul;15(2):199-209. doi: 10.1046/j.1365-313x.1998.00197.x.


Two separate nuclear binding activities (B1 and B2) in the soybean apical hypocotyl have been identified that interact with a palindromic C-box sequence (TGACGTCA) and which are developmentally regulated in an inverse manner. The bZIP factors responsible for these two binding activities, B1 and B2, were isolated from a cDNA library and designated STGA1 and STFs (STF1 and STF2), respectively. Sequence analysis shows that the STFs contain both a zinc-finger domain and a bZIP domain. The two zinc finger sequences of Cys4-Cys4 are most related to the RING zinc-finger motif carrying a Cys3-His-Cys4. In addition the bZIP domain of STFs is highly homologous to the HY5 protein of Arabidopsis. DNA binding studies revealed that STF1 binding to the TGACGT sequence requires distinct flanking sequences. Furthermore, STF1 binds to the Hex sequence as a heterodimer with G-box binding factors (GBFs), a feature not observed with STGA1. Since STF1 expression is most prevalent in apical and elongating hypocotyls, it is proposed that STF1 may be a transcription factor involved in the process of hypocotyl elongation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Basic-Leucine Zipper Transcription Factors
  • Binding Sites
  • DNA, Complementary
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Dimerization
  • G-Box Binding Factors
  • Gene Library
  • Leucine Zippers
  • Molecular Sequence Data
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / metabolism
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Soybean Proteins*
  • Soybeans / metabolism*
  • Transcription Factors / chemistry
  • Transcription Factors / metabolism*
  • Zinc Fingers


  • Basic-Leucine Zipper Transcription Factors
  • DNA, Complementary
  • DNA-Binding Proteins
  • G-Box Binding Factors
  • Nuclear Proteins
  • Recombinant Proteins
  • STF1 protein, Glycine max
  • Soybean Proteins
  • Transcription Factors

Associated data

  • GENBANK/L28003
  • GENBANK/L28004