Defective cyclic adenosine-3', 5'-phosphate-phosphodiesterase regulation in morphogenetic mutants of Dictyostelium discoideum.

Abstract At the end of the growth phase, cells of the slime mould, Dictyostelium discoideum , release an inhibitor of extracellular cAMP-phosphodiesterase into the medium. Non-aggregating mutants or those with atypical cell aggregation were screened for defects in the regulation of the cAMP-phosphodiesterase-inhibitor system. This system was found to be defective in one-half of the mutants selected as morphogenetically aberrant. The mutants were classified as (1) mutants which did not release inhibitor or those with delayed inhibitor release, (2) mutants with excessive phosphodiesterase production and (3) mutants with deficient enzyme activity.