Two tobacco DNA-binding proteins with homology to the nuclear factor CREB

Nature. 1989 Aug 31;340(6236):727-30. doi: 10.1038/340727a0.


The 35S promoter of the cauliflower mosaic virus (CaMV) contains a tandem repeat of the sequence TGACG in the region -83 to -63. This 21-base pair (bp) sequence, called as-1, is involved in root expression of the 35S promoter. When inserted in a promoter of a gene expressed specifically in photosynthetic tissues, as-1 confers high level expression in roots. We have described a factor, ASF-1, that binds specifically to as-1 in vitro. There is a good correlation between ASF-1 binding affinity to as-1 related sequences in vitro and the function of these sequences in vivo. These results strongly suggest that ASF-1 is responsible for the function of as-1. Here we report the isolation of tobacco complementary DNA clones encoding two TGACG-sequence-specific binding-proteins (TGA1a and TGA1b). Sequence analysis of the cDNA clones shows that both proteins contain a basic region that shows high homology to a stretch of basic amino acids in the nuclear factors CREB, GCN4, and c-Jun to a 'leucine-zipper' region. On the basis of binding specificity we propose TGA1a to be a good candidate for ASF-1.

Publication types

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

MeSH terms

  • Activating Transcription Factors
  • Amino Acid Sequence
  • Base Sequence
  • Binding Sites
  • Blood Proteins / genetics*
  • Blood Proteins / metabolism
  • Blotting, Northern
  • Blotting, Southern
  • Cyclic AMP Response Element-Binding Protein
  • DNA / isolation & purification
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / isolation & purification
  • DNA-Binding Proteins / metabolism
  • Leucine / metabolism
  • Molecular Sequence Data
  • Plant Proteins / genetics*
  • Plant Proteins / isolation & purification
  • Plant Proteins / metabolism
  • Plants, Toxic*
  • Sequence Homology, Nucleic Acid
  • Tobacco / genetics*
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism


  • Activating Transcription Factors
  • Blood Proteins
  • Cyclic AMP Response Element-Binding Protein
  • DNA-Binding Proteins
  • Plant Proteins
  • Transcription Factors
  • DNA
  • Leucine