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Fig. 5 ALK6 is required for neural crest development. a When compared to control MO injected embryos, ALK6 morphant embryos showed increased
pigmentation of the head (arrow), ectopic melanocytes in the dorsal fin (arrowheads) and narrower heads reflected by less lateral protrusion of the gills
and smaller distance between the eyes (double arrow). b Cranial cartilage from embryos injected as indicated was stained with Alcian Blue dye. Cartilage
from ALK6 morphant embryos generally showed weaker staining, was smaller (double arrows in B’, B” and B”’) and showed partial or complete loss of
cartilage elements (arrowheads in B’, B” and B”’) of the gills (g) or ceratohyal cartilage (c). The images in A and B show representative examples from one
out of three independent experiments. c Embryos were injected with 1.6 pmol morpholino in one animal-dorsal blastomere at the 8-cell stage as
indicated. A lacZ plasmid was co-injected to identify the injected side, embryos were cultured till stage 13 and stained for LacZ. Expression of msx2 was
analyzed by whole-mount in situ hybridization. Representative images of embryos injected as indicated are shown. Asterisks indicate the injected side.
The results from three independent experiments are summarized in the graph (d). Active BMP signaling at the neural plate border was shown by
whole-mount immunostaining for phosphorylated Smad 1/5/8 (pSmad 1/5/8). e The graph shows a summary of pSmad1/5/8 staining results from two
independent experiments. In (f) representative images of embryos injected with control MO, ALK3MO 1 or ALK6 MO 1 are shown. Embryos were categorized
according to decreased or enhanced msx2 expression or pSmad 1/5/8 staining respectively and differences between indicated groups were analyzed
using the χ2 test. Statistically significant deviations (p-value < 0.01) are indicated by double asterisks; n.s.: not significant |
