Starts and Stops

Science's STKE  27 Aug 2002:
Vol. 2002, Issue 147, pp. tw317-TW317
DOI: 10.1126/stke.2002.147.tw317

In the mammalian ovarian follicle, several layers of somatic granulosa cells surround the oocyte and support its development. Within this structure, the oocyte begins meiosis, but then halts until luteinizing hormone triggers its resumption. How is meiosis halted? Studies to answer this question have been hampered in that removal of the follicle from an oocyte reinitiates meiosis. However, Mehlmann et al. now present a technique in which oocytes can be injected while still surrounded by the follicular cells. The authors show that activity of the G protein Gs is required to maintain the meiotic arrest in oocytes, and they suggest that a signal from granulosa cells may be acting through a receptor to activate the G protein.

L. M. Mehlmann, T. L. Z. Jones, L. A. Jaffe, Meiotic arrest in the mouse follicle maintained by a Gs protein in the oocyte, Science 297, 1343-1345 (2002). [Abstract] [Full Text]