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

Abstract

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.

The ROXY1 C-Terminal L**LL Motif Is Essential for the Interaction with TGA Transcription Factors

“…TGA transcription factors share three highly conserved domains of known functions, including a bZIP involved in DNA binding, nuclear localization, and homodimerization or heterodimerization as well as two Gln-rich domains (Q1 and Q2) involved in transcriptional activation (Katagiri et al, 1989(Katagiri et al, , 1990; Fig. 8A; Supplemental Fig.…”

Expression pattern of a tobacco lipid transfer protein gene within the shoot apex

“…Expression is high in the young leaves and internodes at the top of the plant and declines with age. This pattern of expression is opposite to the one conferred by the TGAl and TAF1 transcription factors and is reminiscent of the expression conferred by a minimal rbcS promoter (Katagiri et a/., 1989;Kuhlemeier et a/., 1988;Oeda etal., 1991). This may make the Ltpl upstream region attractive for studying transcriptional regulation of gene expression.…”

Two bZIP proteins from Antirrhinum flowers preferentially bind a hybrid C‐box/G‐box motif and help to define a new sub‐family of bZIP transcription factors

“…bZIP910, bZIP911, OBF1, MLIP15 (LIP15), LIP19, At7568 (AT7568) and At1507 (AT1507) form a sub-family more closely related to each other in sequence composition of their bZIP domains than to other bZIP proteins. Other bZIP proteins included are CPRF-1, 2 and 3 (Weisshaar et al, 1991) from parsley; TGA1b (Katagiri et al, 1989) from tobacco, GBF1 (Schindler et al, 1992c) from Arabidopsis, GBF9G, (Meier and Gruissem, 1994) from tomato, HBP1a and HBPlac14 (Mikami et al, 1994;Tabata et al, 1989) from wheat, and OHP1 and O2 (Hartings et al, 1989;Pysh et al, 1993) from maize.…”