Fig. 9. Regulation of cortical granule trafficking in C. elegans. Depiction of several steps in cortical granule trafficking and eggshell formation, along with the OID genes involved. Separase localization is indicated. Immature oocytes form cortical granules (red) as they grow while separase remains in the cytoplasm. Just before ovulation, separase accumulates in the nucleus, on oocyte chromosomes (blue) and cytoplasmic filaments. The vitelline layer (brown) separates from the plasma membrane (green) around the time of fertilization (sperm pronucleus in black), and cortical granules cluster near the cortex. Separase is lost from filaments and accumulates on cortical granules as they redistribute in the cortex. Separase is lost during the wave of cortical granule exocytosis in anaphase I. Subsequently, the cargo of cortical granules assembles into the chitin (pink) and lipid (red) layers, which are permeable until late meiosis II.