抄録
The developmental ability of reconstituted embryos that received nuclei from 2-, 4- and 8-cell embryos at M phase of the cell cycle was examined in vitro and in vivo. After fusion of M phase nuclei with enucleated oocytes, the reconstituted oocytes were artificially activated and cultured with cytochalasin B to achieve formation of two “pronuclei-like nuclei” (PN-like nuclei). To obtain embryos with a diploid set of chromosomes, nuclei from each reconstructed embryo were transferred individually into separate enucleated fertilized 1-cell embryos. These nuclear transplants developed to multicellular stages at higher rates and the number of reconstituted embryos doubled. Of the embryos reconstituted with 2-, 4-, and 8-cell nuclei at M phase, 26 (23/88), 40 (32/80) and 4% (5/135) developed to blastocysts, respectively. Live young were produced from blastocysts obtained from reconstituted embryos that received 2- and 4-cell nuclei at M phase, after transfer into recipient females.
