Abstract
Cell fusion is an important process in current animal biotechnology. This study was designed to establish optimal parameters for the electrofusion of hamster 2-cell blastomeres and to examine the dynamic changes in the cytoskeletal distribution using fluorescence staining. Various electric fields (70-2000 V/mm) and durations (50-1000 μsec) of electric pulse were applied. Electric fields higher than 300 V/mm or of duration longer than 200 μsec caused disruption of the blastomere. Blastomere fusion occurred at 70-170 V/mm of 100 μsec duration, with high yields (91%). However, electrofused embryos did not develop. Fluorescence observations showed that the control 2-cell embryos possessed a dense network of microtubules around the nucleus and abundant microfilaments at the cell-to-cell contact region. In the fused embryos, two domains of cytoskeleton, consisting of both microfilaments and microtubules, concentrated around each nucleus were observed. In the embryos which failed to fuse, however, a thin layer of microtubules and very thick bundle of microfilaments appeared at the cell-to-cell contact region. The results suggest that blastomere fusion is accompanied with cytoskeletal reorganization and that dynamic changes of the cytoskeleton occur in different modes between fused and non-fused embryos.
