Transcriptional activator that possesses broad binding specificity for DNA promoter elements with the core sequence 5'-ACGT-3'. May be involved in the regulation of genes expressed during seed development (PubMed:7919992). Binds to the DNA specific sequence 5'-TGAGTCA-3' found in seed storage protein gene promoters (PubMed:11133985). Heterodimer with RISBZ1/BZIP58. Expressed in developing endosperm, especially in aleurone layer cells. Expressed in developing seeds from 10 to 30 days after flowering (DAF).