An oligosaccharide-containing factor that induces cell differentiation in Dictyostelium discoideum.

Abstract

When D. discoideum amoebae (strain V12 M2) are spread at high density on agar containing 1 mM cyclic[c]AMP, essentially all the cells differentiate into stalk cells after 2-3 days. Isolated amoebae plated at low density on agar containing cAMP do not differentiate, but can be induced to do so by a layer of high density helper cells from which they are separated by a thin cellophane membrane. The high density cell popluation releases a dialyzable factor that, with cAMP, can induce isolated amoebae to differentiate into stalk cells. Sugar inhibition, sensitivity to glycosidases and lectin affinity suggest that the differentiation-inducing activity requires the integrity of an oligosaccharide group containing sialic acid, L-fucose, and N-acetylgalactosamine. In addition, a phosphate group appears necessary for biological activity.