Fig 5

Fig 5

(A) Model of target gene expression regulated by distinct pSmad5 levels or distinct durations of BMP signaling. (B) Model of target gene activation after a 30-minute pulse of BMP ligand exposure. If target genes are activated by different pSmad5 levels, then all 3 target genes will be expressed following exposure to high levels of BMP signaling. If differences in signal duration activate BMP target gene expression, then a gene that requires a short signal duration will be expressed, but genes requiring longer signal durations will not be expressed. (C) Experimental schematic of a bmp7 mutant embryo injected with 5 pg of BMP2/7 protein that is fixed 30 minutes postinjection for pSmad5 immunostaining or FISH. (D) Representative immunostaining of pSmad5 intensities of an uninjected bmp7 mutant (n = 8) and a bmp7 mutant injected with 5 pg of BMP2/7 protein (n = 9). Animal pole is facing up. (E–G) Representative FISH in bmp7 mutants uninjected or injected with 5 pg of BMP2/7 protein for sizzled(E) (n = 11 uninjected, n = 11 injected), foxi1(F) (n = 10, n = 11), and bambia(G) (n = 10, n = 11). Animal pole is facing up. A.U. is arbitrary units. BMP, Bone Morphogenetic Protein; FISH, fluorescent in situ hybridization; hpf, hours post fertilization; pSmad5, phosphorylated Smad5; WT, wild-type.