Figure 1. Generating cytoplasts by oocyte enucleation.

Prior to insertion of a foreign nucleus, the native genetic material is removed from the oocyte. Enucleation can be performed without the use of fluorescent dyes; oocytes shown were first enucleated, and then briefly stained with Hoechst 33342 to determine efficiency. The same oocytes are shown for both phase contrast and fluorescence microscopy (left and right panels, respectively). The metaphase plate is clearly visible in all 5 examples of unenucleated oocytes (shown by arrows), with no staining evident in any of the enucleated cells.