NUCLEAR-PROTEIN-780BP FROM CAULIFLOWER BINDS AN ELEMENT IN THE 780-GENE PROMOTER OF T-DNA

A 16 bp site of protein binding has been identified in the promoter of the 780 gene of T-DNA. Specific DNA-protein interactions were demonst rated between a double-stranded oligonucleotide containing this elemen t (5'-TTGAAAAATCAACGCT-3') and a protein isolated from nuclear extract s of cauliflower inflorescences. Specific bases required for this bind ing activity (780 binding protein; 780BP) were defined by kinetic comp etition studies with mutated oligonucleotides, methylation interferenc e assays and DNAse I footprinting. 780BP binding was not competed with up to 1000-fold excess of previously characterized plant regulatory e lements such as as-1, the LRE, and the ocs, G-box, and AT-rich element s. In addition, 780BP was shown to bind sequences overlapping a mammal ian hormone receptor element with greater affinity than the 780 elemen t.