SPORE SWELLING IN DICTYOSTELIUM IS A DYNAMIC PROCESS MEDIATED BY CALMODULIN

Spore swelling is a necessary prelude to the emergence of amoebae duri ng spore germination in Dictyastelium discoideum. Previous work has sh own that the initiation of this event requires the activity of the cal cium-dependent regulatory protein calmodulin. In this study, the use o f trifluoperazine, an inhibitor of calmodulin function, has shown that calmodulin activity is required throughout the swelling phase. When f ully swollen spores were treated with trifluoperazine they rapidly ret urned to the same size and shape observed prior to swelling. These dat a suggest that spore swelling in D. discoideum is a dynamic process wh ich is mediated by calmodulin.