Autoradiographic Localization of Specific Binding of Meiosis-Activating Sterol to Cumulus-Oocyte Complexes from Marmoset, Cow, and Mouse

Faerge, I.; Grøndahl, C.; Ottesen, Jan Lund; Hyttel, Poul

doi:10.1095/biolreprod64.2.527

Cited by 21 publications

(8 citation statements)

References 25 publications

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“…The autoradiographic localization shows specific binding of FF-MAS to oolemma (oocyte plasma membrane), zona pellucida, and cumulus cells. This suggests the existence of a plasma membrane-associated FF-MAS receptor (27), whereas other studies proposed a G proteincoupled receptor mechanism that might be involved in MASsignaling (28). It is thus possible to speculate that MAS actively contributes to sperm-oocyte signaling during the fertilization process.…”

Section: Discussionmentioning

confidence: 89%

A Functional Cytochrome P450 Lanosterol 14α-Demethylase CYP51 Enzyme in the Acrosome: Transport through the Golgi and Synthesis of Meiosis-Activating Sterols

et al. 2004

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Mammalian lanosterol 14 alpha-demethylase (CYP51) is a microsomal cytochrome P450 that demethylates lanosterol to FF-MAS, an oocyte meiosis-activating sterol and late intermediate of cholesterol biosynthesis. Herein we report CYP51 unequivocally localized to acrosomal membranes of male germ cells in mouse, bull, and ram, in which it synthesizes FF-MAS in the presence of the acrosomal form of nicotinamide adenine dinucleotide phosphate reduced-P450 reductase. In the mouse, CYP51 (53 kDa) resides in endoplasmic reticulum (ER) and Golgi during all phases of acrosome development, indicating an intracellular transport from ERs through the Golgi to the acrosome. CYP51 (50 kDa) also resides on acrosomal membranes of bull- and ram-ejaculated sperm. In mouse liver, a 53-kDa CYP51 is no longer detected in trans Golgi, suggesting retrieval back to the ER and no further transport to other organelles. Glycosylated high-molecular-mass CYP51-immunoreactive proteins in acrosomal membranes of bull and ram and Golgi-enriched fractions of mouse liver indicate that mammalian CYP51s are subjected to posttranslational modifications in the Golgi. In conclusion, CYP51 is the first cytochrome P450 enzyme to be detected on acrosomal membranes. It exhibits a unique, cell-type-specific intracellular transport that is in agreement with its cell-type-specific physiological role: production of cholesterol in the liver and sterols with signaling properties in sperm. Demethylation of lanosterol to FF-MAS by the acrosomal lanosterol 14 alpha-demethylase enzyme complex demonstrates for the first time the ability of ejaculate sperm to synthesize meiosis-activating sterols.

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Section: Discussionmentioning

confidence: 89%

A Functional Cytochrome P450 Lanosterol 14α-Demethylase CYP51 Enzyme in the Acrosome: Transport through the Golgi and Synthesis of Meiosis-Activating Sterols

et al. 2004

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“…This product might be cAMP (Yoshimura et al., 1992), protein kinase A (Yu et al., 2002) and C (Quan et al., 2003), mitogen activated protein kinases (Fan et al. 2003), and/or meiosis activating substance (Faerge et al., 2001). The gap junction (GJ) formed between CCs and between CCs and oocytes can help transfer the signals, and then regulate the arrest and meiotic resumption of the enclosed oocytes (Wert and Larsen, 1989).…”

Section: Discussionmentioning

confidence: 99%

Effects of cumulus cells on rabbit oocyte in vitro maturation

Tao

Cao

Zhang

et al. 2008

Animal Physiology Nutrition

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Cumulus cells (CCs) are of great importance in oocyte development and maturation in many species, but detailed influence of CCs has not been extensively examined, especially on rabbit. The present study was designed to investigate the effects of CCs and the elongation of in vitro maturation (IVM) time on rabbit oocyte nuclear and ooplasmic maturation and survival. Cumulus oocyte complexes (COCs) and naked oocytes (NOs) were recovered directly from rabbits super-ovulated with eCG. Corona-enclosed oocytes (COs) and denuded oocytes (DOs) were obtained from COCs after removing a part or whole of CCs. The oocytes were cultured in the following seven groups. (i) Cumulus cell enclosed oocytes (CEOs) were cultured alone (CEOs); (ii) COs were cultured alone (COs); (iii) DOs were cultured alone (DOs); (iv) NOs were cultured alone; (v) DOs were co-cultured with COCs [DOs(COCs)]; (vi) DOs were co-cultured with CCs [DOs(CCs)]; (vii) NOs were co-cultured with CCs [NOs(CCs)]. After the oocytes were cultured for 24 and 30 h, the nuclear maturation was evaluated by first polar body (PB1) extrusion while the ooplasmic maturation was evaluated by the cleavage rate after parthenogenetic activation. The results showed that the nuclear maturation rate of CEOs, COs, DOs(COCs) and DOs(CCs) after 24 h incubation were significantly different from each other (p < or = 0.05), the rate of DOs(CCs) was similar to that of DOs (p > or = 0.05). The cleavage rates in the first two groups were significantly higher than those of the others (p < 0.05). For oocytes cultured for 30 h, the nuclear maturation rates were significantly different for each culture model (p < 0.05). The cleavage rates in first two groups were significantly higher than those of others (p < 0.05). Both the nuclear and cleavage rates significantly increased when the culture time of DOs(COCs) was prolonged from 24 to 30 h. DOs(CCs) nuclear maturation was significantly improved when the culture time was prolonged from 24 to 30 h, but the ooplasmic maturation was not. Few NOs incubated with or without CCs accomplished nuclear maturation (approximately 2% both), even when the culture time was prolonged from 24 to 30 h. The oocyte degeneration rates were significantly different for each culture model after both 24 and 30 h incubation (p < or = 0.05). There was no significant difference in oocyte degeneration in the same groups between 24 and 30 h incubation (p > 0.05). The results suggest that rabbit CCs affect oocyte nuclear and ooplasmic maturation, and their survival. The prolongation of the culture time of rabbit oocyte from 24 to 30 h improves the nuclear and ooplasmic maturation differently in the present system. Rabbit oocytes free of CCs, especially NOs, show weak meiotic resumption potential and compromised viability, which cannot be improved by co-culture with dispersed CCs. The degeneration mostly happens at early time of IVM.

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“…Oocytes were exposed to [ 3 H]-uridine during the first 3 h of maturation. Transmission electron microscopy was carried out as described previously [ 21 ]. Briefly, exposed oocytes were transferred into media with a concentration of 200 μCi/ml [ 3 H]-uridine (Perkin-Elmer).…”

Section: Methodsmentioning

confidence: 99%

Cumulus Cell Transcripts Transit to the Bovine Oocyte in Preparation for Maturation1

Macaulay

Gilbert

Scantland

et al. 2016

Biology of Reproduction

139

105

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So far, the characteristics of a good quality egg have been elusive, similar to the nature of the physiological, cellular, and molecular cues leading to its production both in vivo and in vitro. Current understanding highlights a strong and complex interdependence between the follicular cells and the gamete. Secreted factors induce cellular responses in the follicular cells, and direct exchange of small molecules from the cumulus cells to the oocyte through gap junctions controls meiotic arrest. Studying the interconnection between the cumulus cells and the oocyte, we previously demonstrated that the somatic cells also contribute transcripts to the gamete. Here, we show that these transcripts can be visualized moving down the transzonal projections (TZPs) to the oocyte, and that a time course analysis revealed progressive RNA accumulation in the TZPs, indicating that RNA transfer occurs before the initiation of meiosis resumption under a timetable fitting with the acquisition of developmental competence. A comparison of the identity of the nascent transcripts trafficking in the TZPs, with those in the oocyte increasing in abundance during maturation, and that are present on the oocyte's polyribosomes, revealed transcripts common to all three fractions, suggesting the use of transferred transcripts for translation. Furthermore, the removal of potential RNA trafficking by stripping the cumulus cells caused a significant reduction in maturation rates, indicating the need for the cumulus cell RNA transfer to the oocyte. These results offer a new perspective to the determinants of oocyte quality and female fertility, as well as provide insight that may eventually be used to improve in vitro maturation conditions.

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Autoradiographic Localization of Specific Binding of Meiosis-Activating Sterol to Cumulus-Oocyte Complexes from Marmoset, Cow, and Mouse

Cited by 21 publications

References 25 publications

A Functional Cytochrome P450 Lanosterol 14α-Demethylase CYP51 Enzyme in the Acrosome: Transport through the Golgi and Synthesis of Meiosis-Activating Sterols

A Functional Cytochrome P450 Lanosterol 14α-Demethylase CYP51 Enzyme in the Acrosome: Transport through the Golgi and Synthesis of Meiosis-Activating Sterols

Effects of cumulus cells on rabbit oocyte in vitro maturation

Cumulus Cell Transcripts Transit to the Bovine Oocyte in Preparation for Maturation1

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