Fig. 6

Fig. 6 Pbx and Meis1 act in a cooperative fashion to regulate primitive myelopoietic gene expression. (A–D) Shown are representative embryos following in situ hybridization analysis of pu.1 expression in 24 hpf embryos. Dorsal view of gene expression in the anterior lateral-plate mesoderm (ALPM) is shown in whole-mount embryos with anterior oriented to the left. meis1-morphant (B), Pbx-depleted (C), and meis1-morphant; Pbx-depleted (D) embryos exhibit a severe increase in the number of pu.1-expressing cells when compared to wild type (WT; A) embryos. (E) Quantification of the phenotypes shown in A–D. Shown is the average number of pu.1-expressing cells in the ALPM of 24 hpf embryos as determined by in situ hybridization. Error bars indicate standard error of the mean. *Indicates the difference compared with WT is significant by Student t test; P < 0.0001. **Indicates the difference compared to all other samples is significant by Student t test; P < 0.001. (F–M) Shown are representative embryos following in situ hybridization analysis of pu.1 (F, G) in lateral view, and l-plastin (lcp1; H–J) and lysozyme C (lyz; K–M) expression in dorsal view 24 hpf whole-mount embryos. Pbx-depleted; meis1-morphant embryos (G) exhibit upregulated pu.1 expression in the intermediate cell mass when compared to WT embryos (F). Pbx-depleted (I, L), and meis1-morphant (J, M) embryos exhibit increased numbers of lcp1 and lyz-positive cells in the ALPM when compared to WT embryos (H, K). Genotype of embryos was determined by in situ hybridization analysis of egr2b (F–M) and eng2a (H–J) expression.