Identification of a DNA element that can enhance p53-mediated transactivation

Recent studies have demonstrated that p53 binds to specific DNA sequences and the consensus sequence for the p53 binding site has been proposed. The p53 binding site has also been shown to act as positive p53-responsive element. Here we report the identification of a GC₃ element that enhances p53-mediated transactivation when placed adjacent to the consensus p53 site. The GC₃ element alone cannot act as a positive p53-responsive element. We also show that p53 activates transcription of the c-erbA-α gene through a DNA element that consists of the p53 quarter-sites and GC₃ elements. Using gel mobility-shift assay, we identified a possible GC₃ binding factor distinct from p53.