cAMP and spore differentiation in Dictyostelium discoideum.

Publisher Website
Google Scholar
Abstract
The individual amoebae composing a Dictyostelium aggregate can differentiate into either stalk or spore cells according, it is believed, to the extracellular signals they receive. These signals were identified by inducing the differentiation of isolated cells. Wild-type cells can differentiate into prespore cells in a solution of cAMP plus salts supplemented by conditioned medium. Cell-to-cell contact is not required. Isolated cells of various sporogenous mutant strains form spores in similar conditions without needing conditioned medium at all. For these strains at least, cAMP is the sole inducer necessary for spore formation. Earlier work has shown that stalk cells are induced by a combination of cAMP and a low MW factor, differentiation inducing factor (DIF). DIF now appears to be the only pathway-specific inducer involved in the differentiation of sporogenous amoebae and DIF levels in the aggregate may determine whether an amoeba becomes a stalk or a spore cell. In suitable conditions some sporogenous mutants form migrating slugs having an anterior/posterior pattern of prestalk and prespore cells. This pattern could be generated by the localized activity of DIF.