Interaction of cAMP with the CDC25-mediated step in the cell cycle of budding yeast

Addition of exogenous cAMP to cultures of the start mutant cdc25-1 of Saccharomyces cerevisiae shifted to restrictive temperature causes a partial reversion of the mutated phenotype, with a marked increase of the percentage of budded cells. This effect is coupled to a progression in the cell cycle, as demonstrated by DNA histograms obtained by flow cytometry. Moreover cdc25 cells have a high intracellular cAMP content also at restrictive temperature, and no change in the cAMP content was seen during a transition from restrictive to permissive temperature. These data suggest that CDC25 gene product allows cell proliferation by interacting with a cAMP-mediated mechanism.