The mutation consists of the insertion of phiC31 integrase-specific sequences. The p53 platform consists of a pGK-neomycin selection marker flanked by two attP sites, which replaced sequences from the 5' end of intron 1 to the 5' end of intron 9 (exons 2-9) of the Trp53 gene. PhiC31 integrase- mediated cassette exchange (IMCe) can be achieved using this allele, with the insertion of mutant Trp53 constructs. (J:211918)