An AP1-binding site in the c-fos gene can mediate induction by epidermal growth factor and 12-O-tetradecanoyl phorbol-13-acetate.

We have demonstrated that two sequence elements in the c-fos promoter can mediate the response of the gene to epidermal growth factor and the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA). The first is the previously described serum response element. The second is a sequence element highly homologous to the consensus binding site for the HeLa cell transcription factor AP1. Although recent reports have shown that fos protein binds to AP1-binding sites through an interaction with AP1 protein and have raised the speculation that fos protein may negatively regulate expression of the c-fos gene via this interaction, we found no role for the AP1 consensus homology in the downregulation of c-fos expression following induction by epidermal growth factor and TPA.