Successful transduction of MPG-EGFP into the mouse oocytes. Mature oocytes were obtained from 4-week mouse ovaries, and zona pellucidae were removed by the acid Tyrode solution. EGFP or MPG-EGFP was added to M16 media for 1 hr. Note the strong peripheral EGFP signal in MPG-EGFP treated oocytes. Amiloride, as in HeLa cells, effectively blocked the transduction of MPG-EGFP.