Abstract
The effect of the protein secretion inhibitor, brefeldin-A on the development of mouse 4-cell embryos was investigated. Four-cell embryos of various ages (0, 2, 3, 4, 5, 6, 7, and 8 h post division to the 4-cell stage) were cultured continuously in a medium containing 5 μg/ml brefeldin-A, and the embryos were observed for the evidence of cell division. Developmental rates to the 8-cell stage were significantly lower in embryos cultured with brefeldin-A from 0, 2, 3, 4 and 5 h post division to the 4-cell stage (16.4%, 25.0%, 42.9%, 56.7% and 56.9%, respectively). The embryos placed in BFA from 6, 7 and 8 h post division to the 4-cell stage cleaved normally (85.5%, 94.0% and 100%, respectively). Some of the embryos in which cell division did not occur consisted of 2 or 3 blastomeres that were binucleate. However, when the brefeldin-A application was limited to 6 h, the ability of cell division was reverted (more than 80%). Most of these embryos formed blastocoel cavity by 40 h post division to the 4-cell stage as normal embryos.
