GATA-2 gene dosage has an influence on preservation of hematogenic precursor cells. (A-C) Immunohistochemical analysis of the E9.5 yolk sacs of a wild-type (A), KI-heterozygous (B), and KI-homozygous (C) conceptuses with CD45 antibody. These embryos have 27 to 31 somites. A significantly increased number of CD45⁺ cells were observed in the homozygous mutants. Original magnification, panels A-C, × 100. (D) The number of CD45⁺ cells/500 μm²of wild-type, KI-homozygous (4 embryos each), and KI-heterozygous (3 embryos) yolk sacs are presented as the mean ± standard deviation. (E) Hematopoietic cell production of AGM cells from 3 E11.5 KI-heterozygous mutant embryos and their wild-type littermates. The percentages of CD45⁺ (▦) and CD34⁺ (□) cells harvested on day 10 of culture are plotted.