HSPC numbers are reduced in CHT after 3 dpf in gata2b^−/− embryos. (A) Example of Tg(CD41:GFP); Tg(Flt:RFP) expression in CHT of WT and gata2b^−/− embryos at 76 hpf. (B-D) Quantitation of GFP⁺RFP⁺ cells in WT, gata2b^+/−, and gata2b^−/− embryos at different time points, where each dot represents 1 embryo: 52 to 54 hpf (8.50 ± 1.7 vs 11.86 ± 1.0) (B), 56 to 58 hpf (25.19 ± 3.2 vs 23.25 ± 2.9) (C), and 76 to 78 hpf (55.46 ± 3.8 vs 36.50 ± 3.0; P < .001) (D). Representative example of cmyb expression in WT and gata2b^−/− embryos at 33 hpf (E), and quantitation of signal intensity relative to background at 33 hpf (F), where each dot represents 1 embryo. Representative example of cmyb expression in WT and gata2b^−/− embryos at 56 hpf (G), and quantitation of signal intensity relative to background at 56 hpf (H), where each dot represents 1 embryo. (I) Quantitation of CD41:GFP⁺ cell percentages by flow cytometry at 3, 5, and 20 dpf. (J) Cell-cycle analysis by flow cytometry of Ki67 and 4′,6-diamidino-2-phenylindole (DAPI) staining of CD41:GFP⁺ cells in WT and gata2b^−/− embryos at 75 hpf. (K) Bar graph representing the quantitation of cell cycle of CD41:GFP⁺ cells in WT and gata2b^−/− embryos at 75 hpf. Bars represent mean ± standard error of the mean, with each dot indicating 1 pooled sample. *P < .05, **P < .01.