High-Efficiency Plasmid DNA Transformation in Yeast

Transformation of DNA into cells of the budding yeast Saccharomyces cerevisiae and other industrially important yeasts is most commonly performed using chemical-based methods. Current protocols typically involve exposure of the cells to lithium ions in a solution containing the crowding agent polyethylene glycol (PEG), often in conjunction with other reagents such as dimethyl sulfoxide (DMSO) that promote destabilization of the cell wall and/or cell envelope. Recent work has demonstrated that it is possible to achieve high transformation efficiencies with early stationary phase cells, i.e., small overnight liquid cell cultures, using methods that are rapid and readily scalable for high-throughput projects. Herein, we describe carrier DNAs, chemical reagents, and cell growth media that permit transformation of yeast cells with either plasmids or linear DNA fragments with high efficiency.