nop10 loss results in p53-dependent apoptosis. (A) Western blot analysis of p53 protein stabilization in 4-dpf embryos either untreated or treated with 25 Gy γ-irradiation and incubated for 6 hours. (B) Northern blot analysis of p53 mRNA levels in nop10 mutant embryos compared with wild-type siblings at 4 dpf. (C) Quantification of 3 independent p53 Northern blots comparing the level of p53:actin mRNA by densitometer analysis. (D) Real-time PCR analysis indicating the relative ratios of p53:actin mRNA in individual fractions isolated from polysome profiles of wild-type or nop10 mutants at 4 dpf. Fractions 2 to 4 represent the monosomal portion of the profile, and fractions 5 to 10 represent the polysomal portion. (E) TUNEL assay (focusing on the zebrafish eye) indicating cells undergoing apoptosis in embryos untreated, treated with 25 Gy γ-irradiation and incubated for 6 hours, injected at the 1-cell stage with a p53-MO, or both. Images were obtained using a Nikon Eclipse E600 microscope with 40× Nikon Plan Fluor, 0.75 NA dry objective. A Leica DFC 500 camera was used with Leica Application Suite Version 3.6.0 software.