Fig. 3

Expression of the bre:egfp transgene is globally downregulated by small molecule inhibition of BMP type I receptor-mediated Smad phosphorylation. Embryos were treated with either 0.5% DMSO (a, e, i, k, m, o, q); 10 µM dorsomorphin (DM) (b, f, j, l, n, p, r); 10 µM DMH1 (c, g), or 200 µM SB-431542 (SB) (d, h) between 10 and 24 hpf and imaged shortly after washout. In all images, green indicates bre-driven EGFP expression. Brightfield (a-d) and fluorescent (e-h) images, lateral view, anterior left, 80× magnification. i-r: 2D projections of confocal Z-series showing EGFP and transmission overlays, 400× magnification. Expression domains shown include (i, j) retina; (k, l) hypothalamus (arrow); (m, n) heart (asterisk) and pharyngeal arches (arrow); (o, p) somites; and (q, r) cloaca (arrow). i, j, m-p: Lateral view, anterior left. k, l: Frontal view, left is right. q, r: Ventral view, anterior left.