The Role of Tissue Transglutaminase in the Germinal Vesicle Breakdown of Mouse Oocytes

Centrioles are present in oogonia and oocytes of hamsters, mice, rats, gerbils and man up to the pachytene stage. In subsequent meiotic stages, centrioles are absent. At the time of germinal vesicle breakdown in the mouse several foci composed of electron-dense fibrillar material from which microtubules radiate appear near the nucleus. These fibrillar aggregates, referred to as microtubule foci, form small asters and collectively perform the role of the spindle pole during the two meiotic divisions. There are multiple centres at each pole and their number may vary. Thus, centrioles are not obligatory organelles of the spindle apparatus.

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Inhibition of calcineurin by FK506 stimulates germinal vesicle breakdown of mouse oocytes in hypoxanthine-supplemented medium

PeerJ ◽

10.7717/peerj.3032 ◽

2017 ◽

Vol 5 ◽

pp. e3032

Author(s):

Li Wang ◽

Yan-Hong Zhen ◽

Xiao-Ming Liu ◽

Jing Cao ◽

Yan-Ling Wang ◽

...

Keyword(s):

Culture Medium ◽

Calcineurin Inhibitor ◽

Kinase Inhibitor ◽

Germinal Vesicle ◽

Germinal Vesicle Breakdown ◽

Functional Roles ◽

B Subunit ◽

Mouse Oocytes ◽

A Subunit

Calcineurin (CN) is a serine/threonine phosphatase which plays important roles in meiosis maturation in invertebrate oocytes; however, the role of CN in mouse oocytes is relatively unexplored. In this study, we examined the expression, localization and functional roles of CN in mouse oocytes and granulosa cells. The RT-PCR results showed that theβisoform of calcineurin A subunit (Cn A) expressed significantly higher thanαandγisoforms, and the expression of Cn AβmRNA obviously decreased in oocytes in which germinal vesicle breakdown (GVBD) occurred, while only B1 of calcineurin B subunit (Cn B) was detected in oocytes and stably expressed during oocytes maturation. The following fluorescence experiment showed that Cn A was mainly located in the nucleus of germinal vesicle (GV) stage oocytes and gruanlosa cells, and subsequently dispersed into the entire cytoplasm after GVBD. The decline of Cn A in oocytes suggested that it may play an important role in GVBD. To further clarify the role of calcineurin during meiotic maturation, FK506 (a calcineurin inhibitor) was used in the culture medium contained hypoxanthine (HX) which could keep mouse oocytes staying at GV stage. As expected, FK506 could induce a significant elevation of GVBD rate and increase the MPF level of denuded oocytes (DOs). Furthermore, FK506 could also play an induction role of GVBD of oocytes in COCs and follicles, and the process could be counteracted by MAPK kinase inhibitor (U0126). Above all, the results implied that calcineurin might play a crucial role in development of mouse oocytes and MPF and MAPK pathways are involved in this process.

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Replicating DNA does not block germinal vesicle breakdown in mouse oocytes

Journal of Experimental Zoology ◽

10.1002/jez.1402720310 ◽

1995 ◽

Vol 272 (3) ◽

pp. 245-248 ◽

Cited By ~ 12

Author(s):

J. Fulka ◽

R. M. Moor ◽

J. Fulka

Keyword(s):

Germinal Vesicle ◽

Germinal Vesicle Breakdown ◽

Mouse Oocytes

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Requirement of mosXe protein kinase for meiotic maturation of Xenopus oocytes induced by a cdc2 mutant lacking regulatory phosphorylation sites.

Molecular and Cellular Biology ◽

10.1128/mcb.12.7.3192 ◽

1992 ◽

Vol 12 (7) ◽

pp. 3192-3203 ◽

Cited By ~ 22

Author(s):

K M Pickham ◽

A N Meyer ◽

J Li ◽

D J Donoghue

Keyword(s):

Protein Kinase ◽

Oocyte Maturation ◽

Xenopus Oocytes ◽

Germinal Vesicle ◽

Cyclin B1 ◽

Phosphorylation Sites ◽

Germinal Vesicle Breakdown ◽

Regulatory Phosphorylation

The p34cdc2 protein kinase is a component of maturation-promoting factor, the master regulator of the cell cycle in all eukaryotes. The activity of p34cdc2 is itself tightly regulated by phosphorylation and dephosphorylation. Predicted regulatory phosphorylation sites of Xenopus p34cdc2 were mutated in vitro, and in vitro-transcribed RNAs were injected into Xenopus oocytes. The cdc2 single mutants Thr-14----Ala and Tyr-15----Phe did not induce germinal vesicle breakdown (BVBD) upon microinjection into oocytes. In contrast, the cdc2 double mutant Ala-14/Phe-15 did induce GVBD. Both the Ala-14 and Ala-14/Phe-15p34cdc2 mutants were shown to coimmunoprecipitate cyclin B1 and to phosphorylate histone H1 in immune complex kinase assays. Microinjection of antisense oligonucleotides to c-mosXe was used to demonstrate the role of mos protein synthesis in the induction of GVBD by the Ala-14/Phe-15 cdc2 mutant. Thr-161 was also mutated. p34cdc2 single mutants Ala-161 and Glu-161 and triple mutants Ala-14/Phe-15/Ala-161 and Ala-14/Phe-15/Glu-161 failed to induce GVBD in oocytes and showed a decreased binding to cyclin B1 in coimmunoprecipitations. Each of the cdc2 mutants was also assayed by coinjection with cyclin B1 or c-mosXe RNA into oocytes. Several of the cdc2 mutants were found to affect the kinetics of cyclin B1 and/or mos-induced GVBD upon coinjection, although none affected the rate of progesterone-induced maturation. We demonstrate here the significance of Thr-14, Tyr-15, and Thr-161 of p34cdc2 in Xenopus oocyte maturation. In addition, these results suggest a regulatory role for mosXe in induction of oocyte maturation by the cdc2 mutant Ala-14/Phe-15.

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Pleiotropic effect of okadaic acid on maturing mouse oocytes

Development ◽

10.1242/dev.112.4.971 ◽

1991 ◽

Vol 112 (4) ◽

pp. 971-980 ◽

Cited By ~ 1

Author(s):

H. Alexandre ◽

A. Van Cauwenberge ◽

Y. Tsukitani ◽

J. Mulnard

Keyword(s):

Protein Kinase ◽

Okadaic Acid ◽

Protein Phosphatases ◽

Chromatin Condensation ◽

Polar Body ◽

Germinal Vesicle ◽

Inhibitory Effect ◽

Negative Control ◽

Germinal Vesicle Breakdown ◽

Mouse Oocytes

Okadaic acid (OA), a potent inhibitor of types 1 and 2A protein phosphatases, was shown recently to induce chromatin condensation and germinal vesicle breakdown (GVBD) in mouse oocytes arrested at the dictyate stage by dibutyryl cAMP (dbcAMP), isobutyl methylxanthine (IBMX) and 12,13-phorbol dibutyrate (PDBu). We confirm these results using IBMX and another phorbol diester, 12-O-tetradecanoylphorbol-13-acetate (TPA) and show that OA also bypasses the inhibitory effect of 6-dimethylaminopurine (6-DMAP). It has been concluded that protein phosphatases 1 and/or 2A (PP1, 2A), involved in the negative control of MPF activation, are thus operating downstream from both the protein kinase A and protein kinase C catalysed phosphorylation steps that prevent the breakdown of GV. Similar enzymatic activities are also able to counteract the general inhibition of protein phosphorylation. However, PP1 and/or PP2A are positively involved in the activation of pericentriolar material (PCM) into microtubule organizing centres (MTOCs). This explains the inhibitory effect of OA on spindle assembly. Finally, OA interferes with the integrity and/or function of actomyosin filaments. This results in a dramatic ruffling of the plasma membrane leading to the internalization of large vacuoles, the inhibition of chromosome centrifugal displacement and, consequently, the prevention of polar body extrusion.

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Antioxidants Stimulate Germinal Vesicle Breakdown, But Inhibit Chromosome Formation And Spindle Assembly In Porcine Oocytes

Microscopy and Microanalysis ◽

10.1017/s1431927600037314 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 964-965

Author(s):

Qing-Yuan Sun ◽

Randall S. Prather ◽

Heide Schatten

Keyword(s):

Oocyte Maturation ◽

Germinal Vesicle ◽

Spindle Assembly ◽

Mouse Oocyte ◽

Germinal Vesicle Breakdown ◽

Oocyte Meiosis ◽

First Polar Body ◽

Porcine Oocyte ◽

Chromosome Formation

Mammalian oocytes are arrested at the diplotene stage of the first meiotic division. Release of oocytes from their follicles induces meiotic resumption characterized by germinal vesicle breakdown (GVBD), followed by the chromosome formation and metaphase I spindle organization and finally the extrusion the first polar body. Recently it was shown that cellpermeant antioxidants significantly inhibit spontaneous resumption of meiosis in mouse oocytes, which may indicate a role of oxygen radicals in oocyte maturation. The regulation of mouse oocyte meiosis resumption is different from that of large domestic animals in that GVBD is independent of Ca2+ and protein synthesis. The present study investigated the influence of two cell-permeant antioxidants, 2(3)-ter-butyl-4-hydroxyanisole (BHA) and nordihydroguaiaretic acid (NDGA), on porcine oocyte meiosis resumption, chromatin behavior and spindle assembly. Our findings revealed a different role of antioxidants in porcine oocyte meiosis resumption than in mouse oocyte maturation.

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Involvement of GABAA receptor in Bufo arenarum oocyte maturation

Zygote ◽

10.1017/s0967199408004656 ◽

2008 ◽

Vol 16 (2) ◽

pp. 135-144

Author(s):

G. Sánchez Toranzo ◽

L. Zelarayán ◽

F. Bonilla ◽

J. Oterino ◽

M.I. Bühler

Keyword(s):

Receptor Agonist ◽

Polar Body ◽

Germinal Vesicle ◽

Dependent Manner ◽

Germinal Vesicle Breakdown ◽

First Polar Body ◽

Bufo Arenarum ◽

Turn Over ◽

Pkc Activation

SummaryAmphibian oocytes meiotic arrest is released under the stimulus of progesterone; this hormone interacts with the oocyte surface and starts a cascade of events leading to the activation of a cytoplasmic maturation promoting factor (MPF) that induces germinal vesicle breakdown (GVBD), chromosome condensation and extrusion of the first polar body.The aim of this work was to determine whether the activation of a GABAA receptor is able to induce GVBD in fully grown denuded oocytes of Bufo arenarum and to analyse its possible participation in progesterone-induced maturation. We also evaluated the role of purines and phospholipids in the maturation process induced by a GABAA receptor agonist such as muscimol.Our results indicated that the activation of the GABAA receptor by muscimol induces maturation in a dose- and time-dependent manner and that this activation is a genuine maturation that enables oocytes to form pronuclei. Assays with a receptor antagonist, picrotoxine, showed that the maturation induced by muscimol was inhibited. Treatment with picrotoxine, however, shows that the participation of GABAA receptor in progesterone-induced maturation is not significant.In addition, our results indicate that high intracellular levels of purines obtained by the use of db-AMPc and theophylline or the inhibition of the phosphatidylinositol 4,5-bisphosphate (PIP2 hydrolysis by neomycin and PIP2 turn over by LiCl, respectively, inhibited the maturation induced by muscimol. Treatment with H-7 indicated, however, that PKC activation is not necessary for GVBD induced by the GABAA receptor agonist. Results suggest that the transduction pathway used by the GABAA receptor to induce maturation is different from those used by progesterone.

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The role of calcium in the nuclear maturation of Bufo arenarum oocytes

Zygote ◽

10.1017/s096719940400259x ◽

2004 ◽

Vol 12 (1) ◽

pp. 49-56 ◽

Cited By ~ 4

Author(s):

Liliana I. Zelarayán ◽

Graciela Sánchez Toranzo ◽

Julia M. Oterino ◽

Marta I. Bühler

Keyword(s):

Intracellular Calcium ◽

Germinal Vesicle ◽

Reproductive Period ◽

Protein Kinase Activity ◽

Channel Blockers ◽

Germinal Vesicle Breakdown ◽

Nuclear Maturation ◽

Bufo Arenarum ◽

Hormonal Stimulus

In Bufo arenarum, progesterone is the physiological maturation inducer. However, in this species, oocytes reinitiate meiosis with no need of an exogenous hormonal stimulus when deprived of their enveloping cell, a phenomenon called spontaneous maturation. We demonstrated that in Bufo arenarum spontaneous maturation occurs only in oocytes obtained during the reproductive period, which can be considered competent to mature spontaneously, in contrast to those in the non-reproductive period, which are incompetent. Interestingly, full-grown Bufo arenarum oocytes always respond to progesterone regardless of the season in which they are obtained. There is a general consensus that both a transient increase in intracellular calcium and a decrease in cAMP-dependent protein kinase activity are the first steps in the mechanisms by which progesterone induces maturation in amphibians. In the present work we analysed the role of calcium in the spontaneous and progesterone-induced maturation of Bufo arenarum oocytes. Results demonstrated that the absence of calcium in the incubation medium or the prevention of Ca2+ influx by channel blockers such as CdCl2 or NiCl2 did not prevent meiosis reinitiation in either type of maturation. The inhibition of the Ca2+-calmodulin complex in no case affected the maturation of the treated oocytes. However, when the oocytes were deprived of calcium by incubation in Ca2+-free AR + A23187, meiosis resumption was inhibited. In brief, we demonstrated that in Bufo arenarum the reinitiation of meiosis is a process independent of extracellular calcium at any period of the year and that oocytes require adequate levels of intracellular calcium for germinal vesicle breakdown to occur.

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