Fig. 1

Transplanted neural crest cells transform into muscle cells in the myocardium. (A) Diagram of cell transplantation procedure. Alexa Fluor 488 was injected into donor embryos at the 1-cell stage. At the shield stage, donor cells were transplanted at the position of neural crest to the homotypic position of an age-matched host. This position does not overlap with the ventral and equatorial mesoderm that will give rise to the heart. (B–E) Lateral view, cranial toward left. DIC and fluorescent images are superimposed in left panels, and fluorescent image in right panels. (B, C) At the 8-somite stage, embryos were selected that had transplanted cells (green label) in the neural crest, not in the lateral plate mesoderm or heart-forming precardiac regions (arrowhead). (D, E) At the 26-somite stage, labeled neural crest cells have migrated toward the heart-forming regions (arrow head). (F–I) Confocal cross sections of the heart, dorsal view, cranial to the top. Green (lineage-label) and red channel (MF20 immunofluorescence) overlap in left panels. Lineage-labeled cells were shown in right panels. (F, G) At 3 dpf, in the same embryo as shown above, a lineage-labeled transplanted cell (green label and arrow, G) was detected in the ventricular (V) myocardium, and was MF20-positive (yellow label in overlapped images, F). A indicates the atrium. (H, I) In another embryo, transplanted neural crest cells (arrows) were detected in the bulbus arteriosus (BA) and ventricle (V) and were also MF20-positive (yellow labels in H). Myocardial nuclei are not stained by MF20.