A researcher is studying limb regeneration in the newt Notophthalmus viridescens. She transplants skeletal muscle cells from a transgenic newt that expresses green fluorescent protein (GFP) in all of its cells into the limb of a wild-type recipient newt. She then amputates the recipient limb right at the site of the graft, such that the stump contains GFP-expressing cells. She repeats this experiment several times. Where would you expect to detect GFP in the resulting regenerated limbs?
A) Only in muscle cells. B) Only in skin cells. C) Only in nerve cells. D) Only in muscle and skin cells. E) In all of the cells.