These cells are derived from individual neural crest cells injected with messenger RNA encoding Green Fluorescent Protein (GFP). The top left panel shows the embryonic zebrafish head at 28h. Neural crest derivatives are identified as in Schilling and Kimmel, 1994.

Using this technique, mRNA encoding any potential signaling protein can be introduced into neural crest cells to test the effects on cell fate. We have used it to test the effects of the Wnt signaling pathway.