Genetic Analysis of the Slug Stage of Dictyostelium discoideum

Abstract

During the course of development, cells of Dictyostelium discoideum are able to produce a multicellular body (a ‘slug’) which is capable of movement over the substratum. This phase, which is induced by production of ammonia by the starving cells, may last for hours or days depending on environmental stimuli. In order to probe the regulatory system controlling formation and duration of the slug phase, mutants were isolated that remained in the slug phase for an extended period. Thirty-two such ‘slugger’ mutants were analysed by parasexual genetic techniques and placed into 10 complementation groups (slgA-slgJ). The linkage groups bearing representatives of these complementation groups were determined by segregation of diploids formed between mutants and tester strains. Phenotypic studies of mutants indicated that members of slgD, slgE and slgG were over-sensitive to the ammonia slug-inducing stimulus.