The domain organization of p53 includes two N-terminal transcriptional activation domains (TADs), a proline rich domain, a DNA binding domain, a tetramerization (Tet) domain, and a basic region. The sequence alignment of mouse and human p53 is shown, with the asterisks indicating the location of the mutations in the TAD mutants. The LW residues mutated in p5325,26 knock-in mouse strains correspond to amino acids 25 and 26 in mouse p53 and 22 and 23 in human p53, and the FF residues mutated in the p5353,54 knock-in mouse correspond to amino acids 53 and 54 in both mouse and human p53 (marked in red). A variety of protein cofactors that regulate chromatin remodeling and/or transcriptional initiation interact with p53 via one or both TADs, including the transcriptional regulator proteins TAF6, TAF9, TBP, TRAP80, TFIIH, and histone acetyltransferases p300, CBP, and GCN5, a component of the human STAGA (STP3-TAF(II)31-GCN5-L acetylase) complex. Please note that the exact boundaries of the interaction sites are not precise.