Transcriptional activator that binds specifically to the DNA sequence 5'-TGACG-3'. Recognizes ocs elements like the as-1 motif of the cauliflower mosaic virus 35S promoter. Binding to the as-1-like cis elements mediate auxin- and salicylic acid-inducible transcription. Binds to the hexamer motif 5'-ACGTCA-3' of histone gene promoters. Binds DNA as a dimer. Belongs to the bZIP family.