INHIBITION OF CELL DIFFERENTATION IN A PHOSPHODIESTERASE DEFECTIVE MUTANT OF DICTYOSTELIUM-DISCOIDEUM

A biochemical analysis of a mutant, HP X235, which is dependent upon an exogenous source of a soluble phosphodiesterase in order to aggregate, is presented. The mutant is shown to undertake the developmental changes in its adenylate cyclase activity and to excrete cAMP. Only if the mutant is starved in the presence of an extracellular source of phosphodiesterase are these above changes in adenylate cyclase and cAMP excretion accompanied by increases in cell surface cAMP binding sites, contact A sites and periodic oscillations in light scattering. The data is discussed in terms of the relationship between the generation and perception of the chemotactic signal and cell differentiation to aggregation competence. © 1979.