The Effect of Proteases on Gene Expression and Cell Differentiation in Dictyostelium discoideum

We have examined the effects of chymotrypsin or pronase on the differentiation of monolayers of Dictyostelium discoideum amoebae developing in the presence of 1–5 mM cyclic AMP. Using sporogenous mutants, which are capable of forming both spores and stalk cells under these conditions, we have observed that low concentrations of either protease selectively inhibit a late step of spore formation. Higher levels of the proteases act at an earlier time and by a distinct mechanism to reduce the accumulation of the prespore cell specific enzyme UDP galactose polysaccharide transferase while not affecting the appearance of glycogen phosphorylase. The latter is present in both prestalk and prespore cells.