RNAseq of mutant TP53 HCT116 cell line clones generated via CRISPR editing

To compare the impact of several TP53 mutant variants in an isogenic setting, different TP53 mutations were introduced in HCT116 colorectal carcinoma cells. This parental cell line is wild-type for TP53 and shows a prototypical p53 response. To ensure unambigous genotype-phenotype correlations, the cell were haploidized prior to CRISPR-editing by introducing inactivating deletions of intronic splicing into one of the two TP53 alleles, leaving only one functional copy of TP53. The remaining TP53 allele was altered by inserting a LoxP-flanked transcriptional stop cassette (Lox-Stop-Lox, LSL) into intron 4, which allowed reversible silencing of TP53 expression. The LSL cassette was then specifically targeted with CRISPR/Cas9 to introduce a variety of different mutant p53 alleles. The competency of the mutated p53 allele to induce a p53 response upon activation using Nutlin-3a was then assessed in an RNAseq experiment.