Extraction of DNA from dictyostelium

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. Extraction of genomic DNA is used to clone gene fragments and for analysis of mutants to determine the site of vector integration. Because Dictyostelium cells contain relatively high levels of carbohydrate and nucleases, commercially available DNA preparation kits are not very successful. The DNA isolated according to the following protocol is suitable for digestion by restriction enzymes, amplification by polymerase chain reaction (PCR), and Southern blotting.