The helix-loop-helix transcription factor USF interacts with the basal promoter of human amyloid precursor protein

Nuclear factors from HeLa, PC12, NG108-15 and SK-N-SH cell lines recognized an oligonucleotide (-56 to -37: APP-E1) containing an E box (CANNTG) which had previously been characterized as a DNase I-protected sequence in the basal promoter of the human amyloid precursor protein (APP) gene. Binding to APP-E1 was competed with an oligonucleotide encompassing the recognition site of the transcription factor USF. Antibodies directed against USF interacted with the APP-E1-protein complex and in vitro synthesized USF could bind APP-E1. Co-expression of USF cDNA transactivated a human APP-reporter gene construct. These results suggest that USF may play a role in the expression of the APP gene.