A Human α-Fetoprotein Enhancer-Binding Protein, ATBF1, Contains Four Homeodomains and Seventeen Zinc Fingers

Abstract

We have isolated a full-length cDNA encoding a protein (ATBF1) that binds to an AT-rich motif in the human α-fetoprotein gene enhancer. The amino acid sequence deduced from the cDNA revealed that this is the largest DNA-binding protein (306 kDa) known to date, containing four homeodomains, 17 zinc finger motifs, and a number of segments potentially involved in transcriptional regulation. Although the exact function of this protein has not been determined, these structural features suggest that ATBF1 plays a transcriptional regulatory role.