Effect of spi-1l loss on hematopoiesis. (A) Image of a zebrafish embryo for orientation of the rest of the figure panels. Red box surrounds the yolk (YK) area and blue box surrounds the caudal hematopoietic tissue (CHT). (B-M) Red and blue arrows indicate mRNA expression in the YK and the CHT regions, respectively, of wild-type embryos. Probes for genes and morpholino used are as indicated. (B-G) Lateral view of 28-hpf embryos. Expression of (B) mpx and (C) lcp1 in wild-type sibling embryo. Spi-1l and pu.1 morphant embryos exhibit an almost complete absence of granulocyte (mpx) (D,F) and macrophage (lcp1) (E,G) markers. (H-M) Twenty-two–hpf embryos. (H) Expression of gata1 in control uninjected embryo in the ICM, (I) the head region, demonstrating wild-type gata1 expression in the ICM and absence of expression in the A-LPM. (J) gata1 expression is unchanged in spi-1l morphants in the ICM; (K) there is no expression in the head region. (L) Expression of gata1 in the ICM and (M) ectopic expression of gata1 in the head region of pu.1 morphant.