Primitive erythroid cells in Udu^sq1−/− mutants are defective in cell proliferation and differentiation. (A,D) FACS profile of the cell suspensions from 24-hpf wild-type (A) or Udu^sq1−/− mutant (D) embryos. The y-axis indicates the intensity of the GFP expression; x-axis represents cell size. (B,E) The GFP⁺ hematopoietic cells in panel A (total of 5394 cells) (B) and panel D (total of 6874 cells) (E) are subjected to DNA content analysis by Hoechst 33342 staining. The y-axis indicates the cell number, whereas the x-axis represents the DNA content. The percentages of each phase in cell cycle are given. (C,F) May-Grunwald and Giemsa staining analysis (magnification, × 1000) of sorted GFP⁺ cells in panels A (C) and D (F). Black and red arrows in panel C indicate erythroid and myeloid cells, respectively.