Studies on an Inhibitor of Embryonic Differentiation

Abstract

An inducing factor isolated from 9‐ to 11‐days‐old chicken embryos causes differentiation of the amphibian gastrula ectoderm into mesodermal (trunk and tail) structures. This inducing activity is prevented by an inhibitory factor. The inhibitor is found after gel filtration on Sephadex G‐200 in the void volume. After precipitation with hexadecylpyridinium chloride the inhibitor redissolves at ionic strengths I = 0.4–1.0. In isoelectric focusing experiments the factor bands near pH 3. The inhibitor is tentatively characterized as an acidic glycoprotein.