Fig. 6.

Model of HER2 up-regulation by p53 mutants. Three different molecular mechanisms of how mutant p53 may activate transcription from HER2 promoter are depicted. a Mutant p53 may induce histone (s) acetylation and/or inhibit histone deacetylase (s) causing enrichment of H3 and H4 acetylated forms and chromatin reorganization on the HER2 promoter; b Mutant p53 may induce interaction of one or more transcription factor (s), with the HER2 promoter, such as AP-2 and ETS; c Mutant p53 itself can interact directly on the HER2 promoter. These 3 possibilities are not mutually exclusive and would lead to the HER2 promoter activation with the consequent HER2 gene expression. In this representation, the histones are large blue spheres, the histone H3 acetylated marks are small green circles, the histone H4 acetylated marks are small yellow circles, the mutant p53 proteins are shown as light blue ovals, the AP-2 transcription factor are yellow ovals and ETS are green ovals. The DNA sequence is shown in red