Unlocking p53 response elements: DNA shape is the key.

For recognition of specific regulatory sequences in the genome (i.e., response elements, REs), the tumor suppressor protein 53 kDa (p53) exhibits dose-dependent selectivity. In general, binding to REs linked to target genes involved in the positive regulation of cell death requires higher levels of p53 than those connected to cell survival. Our recent findings provide a mechanistic explanation for this phenomenon. Specifically, we demonstrate that subtle differences in DNA shape, encoded in RE DNA sequence, determine the utilization of two biochemically distinct DNA-binding modes, ultimately connected to different biological outcomes.