VDA-derived Cd41-eGFP⁺ HSPCs are impaired in populating the CHT in cmyb^hkz3 mutants. (A) The cmyb^hkz3/Tg(cd41:eGFP) embryos were injected with DMNB-caged Flu at 1-cell stage. The aortic floor, where Cd41-eGFP⁺ HSPCs will later derive, was labeled by exposure to a pulse flash of UV at 30 hpf. (B) Emergence of eGFP/Flu double-positive cells (right panel, white arrows indicated) were scored and quantified in the CHT 16 hours after UV exposure (left panel). Representative figure was shown in the right panel (eGFP, green; uncaged-Flu, red). Units on the y-axis represent the average number of eGFP/Flu double-positive cells (n ≥ 9, mean ± SD). An asterisk indicates significant difference with sibling (t test, P < .05).