Expression of an altered cAMP binding protein by rapid-developing strains of Dictyostelium discoideum.

Immunoblotting with a monoclonal antibody raised against a novel cAMP binding protein termed CABP1 revealed that the molecular weights of the two CABP1 subunits are altered in certain strains of Dictyostelium discoideum. Cell-free translation followed by immunoprecipitation showed that the altered CABP1 polypeptides are derived from primary translation products. In addition, the affinity of the altered CABP1 for cAMP is much higher than the wild-type form. Morphologically, these strains are indistinguishable from other wild-type strains except that their developmental phase is considerably shorter. The rapid developers also exhibit a precocious appearance of CABP1. These results indicate a good correlation between an altered CABP1 and rapid development.