Updated project metadata. Human PDCD4 wild-type (wt) promoter fragments were amplified from U2OS genomic DNA and X-box deletion mutants (mut) were generated using the QuikChange site-directed mutagenesis kit (Agilent Technologies). DNA probes for affinity purification with the same sequences were obtained by PCR using a biotinylated primer for labeling the 3' end (Thermo Fisher Scientific). DNA affinity purification with nuclear extracts from Nutlin-3a treated U2OS cells.