nop10 loss results in p53-dependent defects in HSC formation. (A) O-Dianisidine staining of whole RBCs at 36 hpf in nop10 mutant embryos or wild-type siblings. (B) In situ hybridization analysis of βE1-globin (36 hpf) or rag-1 (4 dpf) mRNA levels. (C) O-Dianisidine staining in a sampling from 36-hpf clutches of either nop10 mutants (left) and wild-type siblings (arrows indicate mutants) or nop10;p53^M214K/M214K mutants and p53^M214K/M214K siblings (right). (D) Western blot analysis of p53 stabilization in nop10;p53^M214K/M214K embryos compared with p53^M214K/M214K embryos in the presence or absence of 25 Gy γ-irradiation. (E) In situ hybridization analysis of runx-1 mRNA (left) or c-myb mRNA (right) in 36-hpf nop10 mutant embryos compared with clutch siblings either in a p53 wild-type background (top) or p53^M214K/M214K mutant background (bottom). Embryos were mounted in methylcellulose and images were obtained using a Zeiss Axioplan microscope with a 10× Zeiss Neofluor, 0.3 NA dry objective. A Leica DFC 480 camera was used with Leica Application Suite Version 3.5.0 software. (F) Quantification of in situ hybridization results showing percentages of the HSC-loss phenotype in total clutches of embryos.