Evidence that ectoderm influences the differentiation of muscle in the limb of the embryonic chick.
Intact limb buds from stage 19 to 21 embryos differentiate to contain both cartilage and muscle in culture. If the limb ectoderm is removed, the limb mesoderm cells differentiate as cartilage and connective tissue but not as muscle. Intact limb buds from stage 19 embryos differentiate both cartilage and muscle when grafted to the chorioallantoic membrane, but differentiate only cartilage and connective tissue if the ectoderm is removed. The significance of limb ectoderm to muscle differentiation can be observed as late as stage 24. Both the prospective cartilage region and the prospective soft tissue region from the limb of a stage 24 embryo differentiate cartilage and muscle in the presence of limb ectoderm, but differentiate little, if any, muscle in the absence of limb ectoderm. The results indicate that the dorsal and ventral ectoderm have some influence on muscle differentiation.
D000818:Animals; D002356:Cartilage / Q000196:embryology; D002454:Cell Differentiation; D002470:Cell Survival; D002642:Chick Embryo; D006614:Hindlimb / Q000196:embryology; D009132:Muscles / Q000196:embryology*; D009924:Organ Culture Techniques