Fig. 6

Alk receptor signaling is required for both migration and acquisition of mesodermal character of chch-EnR transplanted cells. Transplanted LacZ cells were present in the animal pole at shield stage (A) and were found in anterior neural tissue after 24 hpf (A′). 400 µM SB431542 (Sigma-Aldrich), which inhibits Alk receptors did not alter LacZ donor cell behavior (B-B′). Conversely, chch-EnR donor cells moved from the animal hemisphere to the germ ring by shield stage (C) and were observed in mesodermal structures after 24 hpf (C′). SB431542 treatment results in blocking movement of chch-EnR cells. The donor cells remain in the animal hemisphere at shield stage (D) and are found in anterior neural structures after 24 hpf (D′). This result suggests that signaling via Alk receptors is required for both migration and acquisition of mesodermal character of chch-EnR donor cells. The images in each row are of the same embryo.