Maternal control of mouse preimplantation development.

Mammalian preimplantation development is a process of dedifferentiation from the terminally differentiated eggs to the totipotent blastomeres at the cleavage stage, and then to the pluripotent cells at the blastocyst stage. Maternal factors that accumulate during oogenesis dominate early preimplantation development until the embryonic factors gain control after the activation of the embryonic genome. Recently, a handful of maternal factors that are encoded by the maternal-effect genes have been characterized in genetically modified mouse models. These factors are shown to participate in many aspects of preimplantation development, such as the degradation of maternal macromolecues, epigenetic modification, protein translation, cellular signaling transduction, and cell compaction. Even so, little is known about the interactions between different maternal factors. In this chapter, we have summarized the functions of known maternal factors and hopefully this will lead to a better understanding of the regulation of preimplantation embryogenesis by the maternal regulatory network.