Figure 6. Mdm2 loss leads to activation of p73.

Mdm2^fl/flp53^−/− cells expressing CreER^T2 received 4-OHT or vehicle control (EtOH). A–D) RNA-sequencing was performed after 6hrs (lymphoma) or 48hrs (sarcoma and fibroblasts) of treatment. Gene set enrichment analysis of pooled samples (A, B); normalized enrichment score (NES), nominal (Nom.) P-value, false discovery rate (FDR). Heat-map of individual samples (C) and fold-change of significantly increased p53/p73 target genes in 4-OHT-treated pooled samples relative to vehicle-treated pooled samples (D). Genes verified with qRT-PCR are in gray. E–G) qRT-PCR (triplicate) assessed specific mRNA levels. E, Bax *p=0.00008, Puma *p=0.045, p21 *p=0.0009; F, Bax *p=0.035, Noxa *p=0.001, Puma *p=0.003, p21 *p=0.0005; G, Bax *p=0.0007, Noxa *p=0.009, Puma *p=0.03, p21 *p=0.0001. H) Western blotting CreER^T2 expressing Mdm2^fl/flp53^−/− sarcoma cells after 4-OHT or EtOH. I–K) CreER^T2 expressing Mdm2^fl/flp53^−/− sarcoma cells expressing p73 shRNA (shp73-A or shp73-B) or non-targeting controls (shNT-A or shNT-B). Western blotting following 48hrs of 4-OHT or EtOH (I; cleaved PARP, cPARP). Proliferation (J, MTT assay, quadruplicate); *p<0.002. qRT-PCR (triplicate) for mRNA following 48hrs of 4-OHT or EtOH (K). Bax *p<0.002; Noxa *p<0.0009; Puma *p<0.0007; p21 *p<0.0002.