Fig. 7

Fig. 7 Pbx and Meis1 act upstream of gata1 to regulate the expression of hbae3 and scl, but not lmo2. (A–H) Shown are representative embryos following in situ hybridization analyses of lmo2 and scl expression in lateral view 24 hpf whole-mount embryos. gata1-morphant embryos (B; 100%, n = 11) exhibit near normal lmo2 expression when compared to WT embryos (A). gata1-morphant (D; 100%, n = 7), meis1-morphant (E; 100%, n = 6), and Pbx-depleted (G; 94%, n = 16) embryos exhibit diminished scl expression in the ICM when compared to wild type (WT; C) embryos. meis1-morphant, gata1 RNA-injected embryos (F; 100%, n = 5), and Pbx-depleted, gata1 RNA-injected embryos (H; 95%, n = 19) exhibit greater levels of scl expression than respective meis1-morphant (E) and Pbx-depleted (G) counterparts. Genotype of embryos was determined by in situ hybridization analysis of egr2b expression in hindbrain rhombomeres 3 and 5 (A–H), and eng2a expression in the midbrain hindbrain boundary and muscle pioneers (C–H). (I–L) Shown are representative embryos following in situ hybridization analysis of hbae3 expression in 16 hpf embryos. Dorsal view of PLM gene expression is shown in deyolked, flat-mounted embryos with anterior oriented to the left. Pbx-depleted; meis1-morphant embryos (J; 90%, n = 10) exhibit nearly abolished hbae3 expression when compared to WT embryos (I). gata1 RNA-injected, Pbx-depleted; meis1-morphant embryos (K; 82%, n = 11) exhibit near normal hbae3 expression. gata1 RNA-injected embryos (L; 100%, n = 4) exhibit slightly increased hbae3 expression when compared to WT embryos (I).