|
Fig. 4
Differentially timed induction of bmp4 causes different coloboma phenotypes. (a–e) Gross morphology of (a–d) tg(hsp70:bmp4, cmlc2:GFP) embryos after heat shock at 21, 22, 23 hpf, no heat shock, and (e) wild-type embryos heat shocked at 21 hpf. (a′–h′) Close up, lateral view, (a″–h″) close up, ventral views. Early bmp4 induction impairs optic cup morphogenesis, resulting in coloboma (a′–c″). (f–j) Gross morphology of (f–i) tg(hsp70:bmp4, cmlc2:GFP) embryos after heat shock at 24, 25, 26 hpf, no heat shock and (j) wild-type embryos heat shocked at 24 hpf. (f′–j′) Close up, lateral view, (f″–j″) close up, ventral views. Late bmp4 expression hampers optic fissure fusion, resulting in coloboma (f′–h″). All animals were visualized at 3 to 3.5 dpf. (k–n) Lateral confocal images of larval eyes (3 dpf) stained with DAPI. Individuals were heat shocked at 24 hpf. Tg(hsp70:bmp4, cmlc2:GFP) animals show a persisting optic fissure (k,l) while their wild-type siblings do not (m,n). (k′–n′) are magnifications of the optic fissure region. Notably, the fissure margins are touching in the proximal part of the eye (k′).