nto pBS, then mutated the HindIII site into a FseI site. We next mutated the C-terminal part of the p53 gene in two rounds of PCR mutagenesis, first with primers 5′-GGGCCTGACTCAGACGGATCCCCTCTGCATCCCGTC-3′ and 5′-GACGGGATGCAGAGGGGATCCGTCTGAGTCAGGCCC-3′, which removed the stop codon and introduced a BamHI site, then with primers 5′-GACGGATCCCCTCTGAATTCCGTCCCCATCACCA-3′ and 5′-TGGTGATGGGGACGGAATACAGAGGGGATCCGTC-3′, which introduced an EcoRI site. We verified the sequence from the mutated plasmid, then digested it with BamHI and EcoRI, to insert in frame GFP sequences from a Bam HI-EcoRI fragment of plasmid phr-GFP-1 (Stratagene). We verified the sequence of this p53-GFP fusion fragment, then swapped it in the L3-p53PmlEagPuroΔTK-1L plasmid (see above) by HindIII and FseI digestion, resulting