Fig. 3

pak4 is required for primitive myelopoiesis. (A–C) Inhibition of gata2a expression by MZpak4 knockdown in the posterior blood island (red arrows) in 24-hpf embryos. (D–I) Inhibited expression of the hematopoietic regulatory factor scl in the rostral blood island (RBI; red arrows) at 5-somite stage, lateral view (D–F) and 7-somite stage flat mounts (G–I). (A, D and G) Control morphants, (B, E and H) MZpak4 knockdown embryos. (C, F and I) MZpak4 knockdown embryos rescued by pak4 mRNA injection. (J) Relative expression levels of scl in anterior and posterior regions at 5-somite stage, l-plastin at 15-somite and mpo at 20-somite stages. mRNA levels were measured by QPCR, normalized to 18S rRNA levels and represented as a ratio to the corresponding uninjected control embryos. Samples for anterior and posterior measurement of scl were dissected across the axis as shown while those for l-plastin and mpo were from whole embryos. Results shown are representatives from two individual experiments with similar results.