Transformation of dictyostelium with plasmid DNA by calcium phosphate precipitation

Selection of dictyostelium transformants

INTRODUCTIONDictyostelium discoideum is a unicellular eukaryote often referred to as a social ameba because it can form a multicellular structure when nutrient conditions are limiting. General principles for cell-to-cell communication, intracellular signaling, and cytoskeletal organization during cell motility have been derived from cellular and molecular studies of Dictyostelium and have been found to be conserved across all eukaryotes. The availability of a complete genome database and stocks of wild-type and mutant strains make D. discoideum an accessible and powerful model organism. Dictyostelium is amenable to genetic manipulations that require the introduction of DNA into cells, such as gene knockout, overexpression, antisense RNA expression, RNA interference (RNAi)-mediated gene knockdown, and restriction-enzyme-mediated mutagenesis. Two commonly used methods for DNA-mediated transformation in Dictyostelium are calcium phosphate precipitation and electroporation. Transformants can then be selected in liquid media or on bacterial plates. The latter method reduces the chances of contamination because the cells are grown in buffered agar containing live or dead bacteria, rather than in a rich broth. This method also facilitates the isolation of clones from transformations because each transformant produces a single colony on the plate instead of the pools of transformants obtained in liquid culture. For gene ablation experiments, it is important to obtain a minimum of two independent clones with the same phenotype to exclude the possibility that the phenotype is due to a nonspecific mutation.

Transformation of dictyostelium with plasmid DNA by electroporation

INTRODUCTIONDictyostelium discoideum is a unicellular eukaryote often referred to as a social ameba because it can form a multicellular structure when nutrient conditions are limiting. General principles for cell-to-cell communication, intracellular signaling, and cytoskeletal organization during cell motility have been derived from cellular and molecular studies of Dictyostelium and have been found to be conserved across all eukaryotes. The availability of a complete genome database and stocks of wild-type and mutant strains make D. discoideum an accessible and powerful model organism. Dictyostelium is amenable to genetic manipulations that require the introduction of DNA into cells, such as gene knockout, overexpression, antisense RNA expression, RNA interference (RNAi)-mediated gene knockdown, and restriction-enzyme-mediated mutagenesis. This protocol describes the use of electroporation for DNA-mediated transformation in Dictyostelium.

Dictyostelium discoideum: The Social Ameba

INTRODUCTIONDictyostelium discoideum is a unicellular eukaryote often referred to as a "social ameba" because it can form a multicellular structure when nutrient conditions are limiting. D. discoideum and related organisms, known as the Dictyostelia, have been studied for almost 150 years. The cellular and molecular aspects of their multicellular lifestyle have been studied in detail, and general principles for cell-to-cell communication, intracellular signaling, and cytoskeletal organization during cell motility have been derived from this work and have been found to be conserved across all eukaryotes. The bacteriovore nature of the unicellular stage provides an excellent model in which to study phagocytosis and the mechanisms of bacterial virulence. D. discoideum has also been used successfully to explore the molecular basis of various human diseases, as well as the mechanisms of drug action and the pathways that lead to resistance to certain therapeutic agents. The availability of a complete genome sequence has further widened the scope of studies using D. discoideum. A large potential for secondary metabolism has become apparent, which opens the door to discovering new compounds with potential medical applications. Numerous putative orthologs of genes responsible for diseases in humans, but whose molecular functions are still uncharacterized, are present in the D. discoideum genome. Finally, the availability of community resources, including the genome database dictyBase and the Dicty Stock Center, makes D. discoideum an easily accessible and powerful model organism to study.