Reducing Pu.1 level rescues neutrophil deficit phenotype in runx1^w84x mutants. (A-D) WISH of cebp1 expression in 23 hpf runx1^+/+pu.1^+/+ (A arrows), runx1^+/+pu.1^G242D/G242D (B arrows), runx1^w84x/w84xpu.1^+/+ (C arrow), runx1^w84x/w84xpu.1^G242D/G242D (D arrows). Embryos are viewed dorsally with the anterior to the left. (E-H) SB staining in 36 hpf runx1^+/+pu.1^+/+ (E arrows), runx1^+/+pu.1^G242D/G242D (F arrows), runx1^w84x/w84xpu.1^+/+ (G arrows), and runx1^w84x/w84xpu.1^G242D/G242D (H arrows). (I) Quantification of cebp1⁺ cell numbers in 23 hpf runx1^+/+pu.1^+/+, runx1^+/+pu.1^G242D/G242D, runx1^w84x/w84xpu.1^+/+, and runx1^w84x/w84xpu.1^G242D/G242D embryos. *P < .001 (t test, cebp1_{runx1+/+pu.1+/+}(mean/SE/n) = 50.3/3.1/13, cebp1_{runx1+/+pu.1G242D/G242D} = 51.2/3.7/12, cebp1_{runx1w84x/w84x pu.1+/+} = 11/1.3/10, cebp1_{runx1w84x/w84x pu.1G242D/G242D} = 53.2/4.3/15). (J) Quantification of SB⁺ cell numbers in 36 hpf runx1^+/+pu.1^+/+, runx1^+/+pu.1^G242D/G242D, runx1^w84x/w84xpu.1^+/+, and runx1^w84x/w84xpu.1^G242D/G242D embryos. *P < .01 (t test, SB_{runx1+/+ pu.1+/+} (mean/SE/n) = 105.6/10.7/7, SB_{runx1+/+ pu.1G242D/G242D} = 84.7/13.8/7, SB_{runx1w84x/w84x pu.1+/+} = 28.9/3.9/11, SB_{runx1w84x/w84x pu.1G242D/G242D} = 56.5/7.3/11.