The Cdkn1aSUPER Mouse as a Tool to Study p53-Mediated Tumor Suppression

Summary Cdkn1a , which encodes p21, functions as a major route for p53-mediated cell-cycle arrest. However, the consequence of Cdkn1a gene dosage on tumor suppression has not been systematically investigated. Here, we employed BAC transgenesis to generate a Cdkn1a SUPER mouse, which harbors an additional Cdkn1a allele within its natural genomic context. We show that these mice display enhanced cell-cycle arrest and reduced apoptosis in response to genotoxic stress. Furthermore, using a chemically induced skin cancer model and an autochthonous Kras -driven lung adenocarcinoma model, we show that Cdkn1a SUPER mice display a cancer protection phenotype that is indistinguishable from that observed in Tp53 SUPER animals. Moreover, we demonstrate that Tp53 and Cdkn1a cooperate in mediating cancer resistance, using a chemically induced fibrosarcoma model. Overall, our Cdkn1a SUPER allele enabled us to assess the contribution of Cdkn1a to Tp53 -mediated tumor suppression.