Fig. 2

meis1-morphant embryos exhibit defects in primitive hematopoietic gene expression. Shown are representative embryos following in situ hybridization analysis of hematopoietic marker expression in wild type (WT; A–G) compared with meis1-morphant (A′–G′) embryos. (A–D′) The PLM of 16 hpf flat-mounted, deyolked embryos is shown in dorsal view with anterior to the left. gata1 expression is severely reduced in meis1-morphant embryos (A′; 85%, n = 39) when compared to WT (A). flk1a expression is unchanged in meis1-morphant embryos (B′; 100%, n = 21) when compared to WT (B). Lateral domain of scl (90%, n = 29) and lmo2 expression (79%, n = 24) is abolished in meis1-morphant embryos (C′, D′; red arrowheads), while the medial domain of scl and lmo2 expression is near normal. (E–G′) 24 hpf whole-mount embryos are shown in lateral view with anterior to the left. eng2a expression in the midbrain hindbrain boundary and muscle pioneers (E; black arrowheads) and egr2b expression in hindbrain rhombomeres 3 and 5 (E; bracket) is shown in all panels. gata1 (E′; 91%, n = 53), scl (F′; 97%, n = 35), and lmo2 (G′; 92%, n = 36) expression is reduced in the ICM of meis1-morphant embryos when compared to WT (E–G).