<p>A. <i>p53</i> binds to the <i>p73</i> promoter. EMSA was performed using 32P-labeled 61 bp oligonucleotide (−2634 to −2574) containing putative <i>p53</i>-binding sequence in the <i>p73</i> promoter and nuclear extracts of MCF-7 control and MCF-7/p53siRNA cells. Control and <i>p53</i> knockout (p53−/−) HCT116 cells were used as control. Arrow indicates <i>p53</i> bound to the <i>p73</i> promoter sequence. B. Deletion of <i>p53</i> binding site in the <i>p73</i> promoter did not abrogate <i>p53</i>-knockdown mediated upregulation of <i>p73</i> promoter activity. MCF-7 cells were transfected with the luciferase reporter constructs encoding full length <i>p73</i> promoter, p73PF (PF) or the promoter lacking 61 bp <i>p53</i> binding sequence, p73-PFΔ61 (D61) in the presence or absence of <i>p53</i> knockdown with siRNA.</p
