Omnibank retroviral gene trapping technique

Usp15^−/− mice were generated using the OmniBank retroviral gene-trapping technique (Taconic). The mice were originally in B57BL/6-129 mixed background and subsequently backcrossed for four generations to the C57BL/6 background. USP15^+/− heterozygous mice were bred to generate wild-type (+/+) and KO (−/−) littermates for experiments. Complete ablation of USP15 was confirmed by both IB assays and RT-PCR to amplify different regions of the Usp15 mRNA (primers used are listed in Supplementary Table 1). Mice harboring double deletions of the TCR beta and delta genes (Tcrb/d^−/−) and thus completely lacking T cells were obtained from Jackson Lab (in C57BL/6 background). B6.SJL mice (expressing the CD45.1 congenic marker), Rag1^−/− mice, and the OT-II TCR–transgenic mice (all on C57BL/6 background) were from The Jackson Laboratory. OT-II mice were crossed with the Usp15^−/− mice to generate Usp15^−/− OTII and wild-type OT-II control mice. The p53^−/− mice were from LA Donehower (Baylor College of Medicine) and bred in C57BL6-129 mixed background, and the p53^−/−Mdm2^−/− mice were as described ^{38 (link)}. Mice were maintained in specific pathogen-free facility, and all animal experiments were conducted in accordance with protocols approved by the Institutional Animal Care and Use Committee of the University of Texas MD Anderson Cancer Center.

Usp15^−/− mice were generated using the OmniBank retroviral gene-trapping technique (Taconic). The mice were originally in C57BL/6-129 mixed background and subsequently backcrossed for six generations to the C57BL/6 background. Heterozygous (Usp15^+/−) mice were bred to generate age-matched wildtype (Usp15^+/+) and homozygous Usp15-KO (Usp15^−/−) experimental mice. Tcrb^−/−Tcrd^−/− mice, Rag1^−/− mice and OT-I TCR-transgenic mice were obtained from Jackson Laboratory. Mice were maintained in specific pathogen-free facility, and all animal experiments were conducted in accordance with protocols approved by the Institutional Animal Care and Use Committee of the University of Texas MD Anderson Cancer Center.