An insertional mutagenesis approach to Dictyostelium cell death.

Programmed cell death (PCD) in Dictyostelium shows a pattern of ordered degeneration similar to that observed in higher eukaryotes but somewhat different from the most studied form of PCD, i.e. apoptosis. To contribute to a genetic definition of this process, Dictyostelium HMX44A cells have been subjected to insertional mutagenesis, followed by selection based on several rounds of differentiation/regrowth to recover only cells resistant to death. We describe here the approach used, a partial characterization of the first mutant thus obtained called C5 showing some dissociation of cell death signs, and, in this case where plasmid rescue was not possible, as a first step towards identification of the gene at play recovery of genomic flanking sequences via genomic recircularization and PCR. This work demonstrates the feasibility of an insertional mutagenesis approach to obtain death-resistant mutants in Dictyostelium.