Two tobacco DNA-binding proteins with homology to the nuclear factor CREB.
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.
Katagiri
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F
Laboratory of Plant Molecular Biology, Rockefeller University, New York 10021.
Lam
E
E
Chua
N H
NH
D051696:Activating Transcription Factors; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D001798:Blood Proteins / Q000235:genetics* / Q000378:metabolism; D015152:Blotting, Northern; D015139:Blotting, Southern; D017362:Cyclic AMP Response Element-Binding Protein; D004247:DNA / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D010947:Plants, Toxic; D012689:Sequence Homology, Nucleic Acid; D014026:Nicotiana / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D051696:Activating Transcription Factors; D001798:Blood Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D014157:Transcription Factors; D004247:DNA; D007930:Leucine