During female gamete production oocytes arrest during the diplotene stage of meiosis I before completing diakinesis and moving into meiosis II. In response to hormones, oocytes resume and complete meiosis to produce the final mature gametes. In C. elegans, meiotic maturation is triggered by major sperm protein through G-alpha-S-adenylate cyclase - protein kinase A (PKA) signaling and soma-to-germline communication.
Oogenesis is the process of generating functional oocytes from an undifferentiated germ cell. In most animal species, oocytes arrest during meiotic prophase. The completion of meiosis and the preparation of the oocyte for fertilization are triggered in response to intercellular signaling in a process called meiotic maturation. During meiotic maturation, the oocyte transitions to metaphase of meiosis I, the nuclear envelope breaks down, the cortical cytoskeleton undergoes rearrangement, and the meiotic spindle is assembled. By contrast, in C. elegans, the processes of meiotic maturation, ovulation, and fertilization are temporally coupled. Meiotic maturation is triggered by major sperm protein (MSP), which acts as a hormone. In turn the maturing oocyte signals its own ovulation. During ovulation the oocyte passes through the spermatheca becoming fertilized on the way to the uterus.