Figure 3

Stag mutations alter the number of gata1- and spi1-positive cells in 24 hpf zebrafish embryos. (A) Lateral views of gata1 expression in whole-mount embryos at 24 hpf; anterior to the left. gata1 expression is reduced in stag1a^nz204+/- and stag1a^nz204-/- embryos and is rescued upon injection of functional stag1a mRNA. gata1 expression is reduced in stag2b^nz207+/- and stag2b^nz207-/- embryos and is rescued upon injection of functional stag2b mRNA. Reduced expression is indicated by arrows. (B)spi1 expression in whole-mount embryos at 24 hpf. Left panels show lateral views and right panels show ventral views; anterior to the left. The number of spi1-positive cells is increased in stag1a^nz204+/- and stag1a^nz204-/- embryos (yellow arrows). spi1 expression in stag2b^nz207 heterozygous embryos and stag2b^nz207 homozygous mutant embryos is comparable to wildtype. Scale bars are 100 μm. The number of embryos is indicated in lower-right-hand corners. (C) mRNA levels of haematopoietic stem cell marker cmyb and erythroid or myeloid lineage markers in stag1a^nz204 and stag2b^nz207 homozygous mutant embryos at 48 hpf. The bar graph shows the mean +/- one standard deviation. *P ≤ 0.05, **P ≤ 0.01; one-way ANOVA. Expression was normalized to the reference gene, b-actin.