Transformation of Intact Cells of Saccharomyces cerevisiae: Lithium Methods and Possible Underlying Mechanism

Abstract

Since it was initially established, the lithium method for transforming Saccharomyces cerevisiae intact cells has been modified, and a possible underlying mechanism has been elucidated. This method requires polyethylene glycol (PEG) and transformation efficiency is enhanced by lithium and single-stranded carrier DNA (ssDNA). Here, we describe the original lithium method, the modified method, and the possible underlying mechanism, in which plasmid DNA that was absorbed onto the cell wall enters into the cells via endocytotic membrane invagination and lithium and ssDNA synergistically alter cell wall structure and enhance transformation efficiency.