The Role of Autophagy during Early Embryogenesis in Mice

Abstract

During oogenesis, oocytes accumulate maternal mRNAs and proteins. After fertilization however, these maternal products are rapidly degraded and new products encoded by the zygotic genome are synthesized. This transition is critical for preimplantation embryonic development. Since the transition occurs rapidly after fertilization, it is reasonable that large scale of degradation systems could be involved in this transition. Autophagy is a cytoplasmic degradation system mediated by lysosome. Whether autophagy is essential for early embryogenesis has been controversial. We recently found that autophagy is highly induced soon after fertilization. Using oocyte-specific Atg5 knockout mice, we revealed that autophagy-deficiency caused embryonic lethality at four-to-eight cell stage embryos. Thus, our results suggested that autophagy is essential for oocyte-to-embryo transition.