nop10 loss causes rpS7 binding to Mdm2 and increased degradation of rpS7. (A; left) Immunoprecipitation of embryo lysates at 4 dpf with preimmune serum or αrpS7 followed by blotting with αMdm2 (top) or αrpS7 (bottom). (Right) A total of 50 μg (5%) of total lysate used for immunoprecipitations blotted with either αrpS7 or αMdm2 (note: these samples are on the same blots as the immunoprecipitations but are displayed separately because of different exposure requirements). (B) Western blot analysis of levels of rpS7, rpL11, rpL5, and actin in wild-type and nop10 mutant embryos treated with cycloheximide for 0 to 4 hours. (C) Quantification of 3 independent experiments indicating the protein with the largest fold decrease of expression in 4 hours after cycloheximide treatment is rpS7 in nop10 mutant embryos. (D) Western blot analysis of 2 dpf wild-type embryos untreated or treated with 25 Gy γ-irradiation, nop10 mutants, or nop10;rpS7 mutants. (E) Densitometer quantification of expression levels in panel D comparing relative p53/actin ratios, setting the wild-type γ-ratio to 1.