Activation of the meiotic divisions in Drosophila oocytes.

Key meiotic events in many organisms are controlled at the translational level. In this study, we examine the role of translational regulation in the meiotic cell cycle of Drosophila. In order to address this question, we developed a system for activating Drosophila oocytes in vitro. With this method, hundreds of mature oocytes can be activated to resume and complete meiosis. The stages of meiosis are normal by cytological criteria, and the timing of the meiotic divisions is similar to that of eggs activated in vivo. We use this system to examine the role of protein synthesis in regulating the progression of meiosis and the maintenance of the metaphase I arrest. We find that synthesis of new proteins after metaphase I is not required for anaphase I, meiosis II, or the decondensation of the meiotic products. Also, continued protein synthesis is not required to maintain the metaphase I arrest. New protein synthesis is required, however, for proper chromatin recondensation after meiosis.