GAL4 is a transcriptional activator which activates genes necessary for galactose catabolism. The DNA binding domain of GAL4 is contained in the first 74 amino acids and contains a zinc finger sequence motif. However, amino acids 1-147 have been shown to bind to DNA in vitro. While GAL4 (1-74) bind DNA specifically, it is with a lower affinity than the GAL4 (1-147). GAL4 (1-147) binds to a specific 17 base pair nucleotide sequence, but alone is insufficient to activate transcription. Either of the two acidic activating regions, activating region I (amino acids 148-238) or activating region II (amino acids 768-881), must be joined to activate transcription.