TRANSFORMATION OF INTACT-CELLS OF SACCHAROMYCES-CEREVISIAE BY SQUARE-WAVE PULSES USING CASTELLATED MICROELECTRODES

Genetic transformation of intact cells of Saccharomyces cerevisiae wit h an expression vector pYES 2, to efficiencies of 10(5) to 10(6) by hi gh voltage electroporation is presented. Prototrophic transformants of yeast expressing resistance to ampicillin were obtained by subjecting the mixture of cells and DNA to a single square wave pulse at an ampl itude of 2.5, 2.75 and 3.0 kV/cm in combination with a pulse width of 4, 5 and 3 msec for the three different strains Y915, Y742 and INVSC 1 respectively. The critical factors and electrical parameters which de termine the transformation efficiency were examined. This communicatio n describes the optimal conditions for reproducible and high efficienc y transformation of yeast by the method of electroporation.