Figure 2.

Putative mechanism of S. cerevisiae transformation. DNA initially attaches to the cell wall. PEG is indispensable for this attachment and for successful transformation of intact cells. PEG also possibly acts on the membrane to increase the transformation frequency and efficiency as well as the permeability to YOYO-1. The attached DNA passes through the cell wall. LiAc and heat shock help DNA to pass through the cell wall. DNA then enters into the cell via endocytotic membrane invagination. Some DNA in the endosomes is delivered to the vacuoles and digested. However, the manner in which DNA escapes digestion, reaches the nucleus and enters it through the nuclear pore is still unclear.