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In nearly every vertebrate species, elevated intracellular cAMP maintains oocytes in prophase I of meiosis. Prior to ovulation, gonadotropins trigger various intra-ovarian processes, including the breakdown of gap junctions, the activation of EGF receptors, and the secretion of steroids. These events in turn decrease intracellular cAMP levels in select oocytes to allow meiotic progression, or maturation, to resume. Studies suggest that cAMP levels are kept elevated in resting oocytes by constitutive G protein signaling, and that the drop in intracellular cAMP that accompanies maturation may be due in part to attenuation of this inhibitory G protein-mediated signaling. Interestingly, one of these G protein regulators of meiotic arrest is the Galpha(s) protein, which stimulates adenylyl cyclase to raise intracellular cAMP in two important animal models of oocyte development: Xenopus leavis frogs and mice. In addition to G(alpha)(s), constitutive Gbetagamma activity similarly stimulates adenylyl cyclase to raise cAMP and prevent maturation in Xenopus oocytes; however, the role of Gbetagamma in regulating meiosis in mouse oocytes has not been examined. Here we show that Gbetagamma does not contribute to the maintenance of murine oocyte meiotic arrest. In fact, contrary to observations in frog oocytes, Gbetagamma signaling in mouse oocytes reduces cAMP and promotes oocyte maturation, suggesting that Gbetagamma might in fact play a positive role in promoting oocyte maturation. These observations emphasize that, while many general concepts and components of meiotic regulation are conserved from frogs to mice, specific differences exist that may lead to important insights regarding ovarian development in vertebrates.
Albertini,
Comparative aspects of meiotic cell cycle control in mammals.
1998, Pubmed
Albertini,
Comparative aspects of meiotic cell cycle control in mammals.
1998,
Pubmed
Albertini,
Cellular basis for paracrine regulation of ovarian follicle development.
2001,
Pubmed
Cato,
Rapid actions of steroid receptors in cellular signaling pathways.
2002,
Pubmed
Edwards,
Regulation of signal transduction pathways by estrogen and progesterone.
2005,
Pubmed
Federman,
Hormonal stimulation of adenylyl cyclase through Gi-protein beta gamma subunits.
1992,
Pubmed
Fortune,
Steroid production by Xenopus ovarian follicles at different developmental stages.
1983,
Pubmed
,
Xenbase
Gallo,
Stimulation of Xenopus oocyte maturation by inhibition of the G-protein alpha S subunit, a component of the plasma membrane and yolk platelet membranes.
1995,
Pubmed
,
Xenbase
Gill,
Androgens promote maturation and signaling in mouse oocytes independent of transcription: a release of inhibition model for mammalian oocyte meiosis.
2004,
Pubmed
Guzmán,
A Gbetagamma stimulated adenylyl cyclase is involved in Xenopus laevis oocyte maturation.
2005,
Pubmed
,
Xenbase
Haas,
The modulator of nongenomic actions of the estrogen receptor (MNAR) regulates transcription-independent androgen receptor-mediated signaling: evidence that MNAR participates in G protein-regulated meiosis in Xenopus laevis oocytes.
2005,
Pubmed
,
Xenbase
Hammes,
Steroids and oocyte maturation--a new look at an old story.
2004,
Pubmed
,
Xenbase
Hinckley,
The G-protein-coupled receptors GPR3 and GPR12 are involved in cAMP signaling and maintenance of meiotic arrest in rodent oocytes.
2005,
Pubmed
,
Xenbase
Jamnongjit,
Epidermal growth factor receptor signaling is required for normal ovarian steroidogenesis and oocyte maturation.
2005,
Pubmed
Kelly,
Estrogen signaling in the hypothalamus.
2005,
Pubmed
Levin,
Integration of the extranuclear and nuclear actions of estrogen.
2005,
Pubmed
Lieberman,
Oocytic meiosis in cultured rat follicles during inhibition of steroidogenesis.
1976,
Pubmed
Lutz,
G protein beta gamma subunits inhibit nongenomic progesterone-induced signaling and maturation in Xenopus laevis oocytes. Evidence for a release of inhibition mechanism for cell cycle progression.
2000,
Pubmed
,
Xenbase
Lutz,
Evidence that androgens are the primary steroids produced by Xenopus laevis ovaries and may signal through the classical androgen receptor to promote oocyte maturation.
2001,
Pubmed
,
Xenbase
Lutz,
Selective modulation of genomic and nongenomic androgen responses by androgen receptor ligands.
2003,
Pubmed
,
Xenbase
Maller,
Regulation of oocyte maturation.
1980,
Pubmed
,
Xenbase
Mehlmann,
The Gs-linked receptor GPR3 maintains meiotic arrest in mammalian oocytes.
2004,
Pubmed
Mehlmann,
Meiotic resumption in response to luteinizing hormone is independent of a Gi family G protein or calcium in the mouse oocyte.
2006,
Pubmed
Mehlmann,
Meiotic arrest in the mouse follicle maintained by a Gs protein in the oocyte.
2002,
Pubmed
Romo,
G(alpha)s levels regulate Xenopus laevis oocyte maturation.
2002,
Pubmed
,
Xenbase
Sadler,
Inhibition of Xenopus oocyte adenylate cyclase by progesterone: a novel mechanism of action.
1985,
Pubmed
,
Xenbase
Sadler,
Progesterone inhibits adenylate cyclase in Xenopus oocytes. Action on the guanine nucleotide regulatory protein.
1981,
Pubmed
,
Xenbase
Shaul,
Regulation of endothelial nitric oxide synthase: location, location, location.
2002,
Pubmed
Sheng,
Regulation of Xenopus oocyte meiosis arrest by G protein betagamma subunits.
2001,
Pubmed
,
Xenbase
Sheng,
Co-operation of Gsalpha and Gbetagamma in maintaining G2 arrest in Xenopus oocytes.
2005,
Pubmed
,
Xenbase
Smith,
The interaction of steroids with Rana pipiens Oocytes in the induction of maturation.
1971,
Pubmed
Wang,
Protein kinase A(PKA)-restrictive and PKA-permissive phases of oocyte maturation.
2006,
Pubmed
,
Xenbase
Wang,
Progesterone inhibits protein kinase A (PKA) in Xenopus oocytes: demonstration of endogenous PKA activities using an expressed substrate.
2004,
Pubmed
,
Xenbase
White,
Specific modulation of nongenomic androgen signaling in the ovary.
2005,
Pubmed
,
Xenbase
Wong,
Estrogen receptor-interacting protein that modulates its nongenomic activity-crosstalk with Src/Erk phosphorylation cascade.
2002,
Pubmed
Yang,
Xenopus laevis ovarian CYP17 is a highly potent enzyme expressed exclusively in oocytes. Evidence that oocytes play a critical role in Xenopus ovarian androgen production.
2003,
Pubmed
,
Xenbase
