Cell differentiation in the absence of intracellular and extracellular cyclic AMP pulses in Dictyostelium discoideum

Abstract The mutant HSB1 was obtained by colony immunoblotting of mutagenized Dictyostelium discoideum cells with a monoclonal antibody against contact site A, a membrane glycoprotein. HSB1 cells undergo early development in the absence of intracellular and extracellular cAMP pulses. The receptor-mediated activation of adenylate cyclase is defective, but the basal activity increases normally during the first hours of development. Other preaggregative gene products, such as the inhibitor of phosphodiesterase, the contact site A glycoprotein, EDTA-stable contacts, and four developmentally regulated gene transcripts are also expressed in the mutant. Postaggregative gene transcripts fail to accumulate, even after pulsatile addition of cAMP. However, complete development of mutant cells is obtained by complementation with cells of the parent strain AX2.