siRNA-mediated depletion of stable proteins in mouse oocytes

Maternal proteins stored in mammalian oocytes play various roles in meiotic maturation, fertilization, and preimplantation development. To understand biological functions and molecular mechanisms underlying the dynamic developmental processes, it is necessary to deplete maternal proteins in oocytes. However, it is often difficult to achieve this by RNAi introduction into GV- or MII-stage oocytes because of the high stability of target proteins. Here we describe a novel knockdown system that allows depleting even stable proteins in mouse oocytes. In this system, follicles are collected from 12-day-old mice and oocytes within the follicles are injected with siRNA, and then the injected follicles are cultured in vitro for 12 days until the oocytes reach the fully grown stage. Application of this method will greatly help reveal the mechanism and function of molecular events occurring in mouse oocytes and preimplantation embryos