BBR-BPC Transcription Factor Family
This family includes gbp a protein from Soybean that binds to GAGA element dinucleotide repeat DNA. It seems likely that the
this domain mediates DNA binding. This putative domain contains several conserved cysteines and a histidine suggesting this
may be a zinc-binding DNA interaction domain.
The barley b recombinant (BBR) protein binds specifically to the (GA/TC)8 repeat. BBR is nuclear targeted and is a
characterized nuclear localization signal (NLS) sequence, a DNA-binding domain extended up to 90 aa at the C-terminus and a
putative N-terminal activation domain. The corresponding gene has no introns and is ubiquitously expressed in barley
tissues. In co-transfection experiments, BBR activates (GA/TC)8-containing promoters, and its overexpression in tobacco
leads to a pronounced leaf shape modification. BBR has properties of a GAGA-binding factor, but the corresponding gene has
no sequence homology to Trl and Psq of Drosophila, which encode functionally analogous proteins.
We identified BASIC PENTACYSTEINE1 (BPC1) as a regulator of the homeotic Arabidopsis thaliana gene SEEDSTICK (STK), which
con trols ovule identity, and characterized its mechanism of action. A combination of tethered particle motion analysis and
elect romobility shift assays revealed that BPC1 is able to induce conformational changes by cooperative binding to
purine-rich ele ments present in the STK regulatory sequence. Analysis of STK expression in the bpc1 mutant showed that STK
is upregulated. O ur results give insight into the regulation of gene expression in plants and provide the basis for further
studies to underst and the mechanisms that control ovule identity in Arabidopsis. In the dominant mutant Hooded (K), the
barley gene BKn3 is overexpressed as a result of a duplication of 305 bp in intron IV. When fused to a cauliflower mosaic
virus 35S minimal promoter, the 305 bp element activates gene expression in tobacco, as d oes a 655 bp BKn3 promoter
sequence. Both DNA fragments contain a (GA)8 repeat (GA/TC)8. A one-hybrid screen using the 305 bp element as the DNA target
led to the cloning of the barley b recombinant (BBR) protein, which binds specifically to the (GA/ TC)8 repeat. BBR is
nuclear targeted and is a characterized nuclear localization signal (NLS) sequence, a DNA-binding domain extended up to 90
aa at the C-terminus and a putative N-terminal activation domain. The corresponding gene has no introns and is ubiquitously
expressed in barley tissues. In co-transfection experiments, BBR activates (GA/TC)8-containing promoters, an d its
overexpression in tobacco leads to a pronounced leaf shape modification. BBR has properties of a GAGA-binding factor, b ut
the corresponding gene has no sequence homology to Trl and Psq of Drosophila, which encode functionally analogous proteins.
In Arabidopsis, (GA/TC)8 repeats occur particularly within 1500 bp upstream of gene start codons included in some homeodoma
in genes of different classes. The data presented suggest that expression of the barley BKn3 is regulated, at least in part,
by the binding of the transcription factor BBR to GA/TC repeats.
21 putative BBR-BPC TF peptide,
CDS, and cDNA sequences;
blast HSP, and gene level multiple sequence alignment in
Soy - TFKB.
21 DUF1004 domain peptide sequences with
alignement, and phylogeny tree.
9 BBR-BPC protein
and DNA
sequences
with
annotations for soybean in PlantTFDB. Most are partial sequences.
This page was setup on May 27, 2009,
last updated by Dr. Jeff Chen on
June 16, 2009.
