Up-regulation of p53 activity partially contributes to the erythroid phenotype in Udu^sq1−/− mutants. (A-B) WISH shows that p53 expression is elevated in 24-hpf Udu^sq1−/− embryos (B) compared with wild-type (A). (C-E) WISH of band3 in 22-hpf wild-type embryos (C) and Udu^sq1−/− mutant embryos injected with control MO (D) or p53 MO (E). (F-H) o-dianisidine staining of 2-dpf wild-type embryo (F) and Udu^sq1−/− mutant embryos injected with control MO (G) or p53 MO (H). (I-K) WISH of gadd45αl in 24-hpf wild-type embryos (I) and Udu^sq1−/− mutant embryos injected with control MO (J) or p53 MO (K). All embryos are in lateral views with anterior to the left. Arrows in panels F and H indicate o-dianisidine–stained red blood cells.