PLCz-induced Ca2+ oscillations are enhanced after germinal vesicle breakdown during mouse oocyte maturation

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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mInscuteable regulates meiotic spindle organization during mouse oocyte meiotic maturation

Zygote ◽

10.1017/s0967199419000613 ◽

2019 ◽

Vol 28 (1) ◽

pp. 45-50

Author(s):

Zhuoni Xiao ◽

Jiali Peng ◽

Meiting Xie ◽

Jing Yang ◽

Wangming Xu

Keyword(s):

Oocyte Maturation ◽

Germinal Vesicle ◽

Asymmetric Division ◽

Mouse Oocyte ◽

Meiotic Spindle ◽

Meiotic Maturation ◽

Cellular Polarity ◽

Germinal Vesicle Breakdown ◽

Key Events ◽

Oocyte Meiotic Maturation

SummaryEstablishment of cellular polarity is one of the key events during oocyte maturation. Inscuteable (Insc) has been identified as a key regulator of cell polarity during asymmetric division in Drosophila. However, the function of its evolutionarily conserved mammalian homologue, mInscuteable (mInsc), in mouse meiotic maturation is not clear. In this study, we investigated the roles of mInsc in mouse oocyte maturation. mInsc was detected at all stages of oocyte maturation. The protein level of mInsc was slightly higher at the germinal vesicle breakdown (GVBD) stage and remained constant during mouse oocyte maturation. The subcellular localization of mInsc overlapped with spindle microtubules. Disruption of microtubules and microfilaments caused changes in the localization of mInsc. Depletion or overexpression of mInsc significantly decreased the maturation rates of mouse oocytes. Depletion of mInsc significantly affected asymmetric division, spindle assembly, alignments of chromosomes and actin cap formation. Taken together, our results demonstrated that mInsc regulates meiotic spindle organization during mouse meiotic maturation.

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SUMOylation regulates germinal vesicle breakdown and the Akt/PKB pathway during mouse oocyte maturation

AJP Cell Physiology ◽

10.1152/ajpcell.00038.2018 ◽

2018 ◽

Vol 315 (1) ◽

pp. C115-C121 ◽

Cited By ~ 7

Author(s):

Weber Beringui Feitosa ◽

Patricia L. Morris

Keyword(s):

Cell Cycle ◽

Oocyte Maturation ◽

Nuclear Translocation ◽

Germinal Vesicle ◽

Mouse Oocyte ◽

Serine Phosphorylation ◽

Germinal Vesicle Breakdown ◽

Akt Activation ◽

Downstream Target

SUMOylation, a process of posttranslational modification of proteins by the small ubiquitin-related modifier (SUMO) family of proteins, is known to be involved in yeast and mammalian somatic cell-cycle regulation. However, the identities of the SUMO-modified oocyte targets are largely unknown and the functional role(s) for SUMOylation during mammalian oocyte maturation remains unclear. On the basis of studies in non-germline cells, protein kinase B/Akt is a potential SUMOylation target in the mouse oocyte, where it plays an essential role in cell-cycle resumption and progression during maturation. This study investigated the temporal patterns and prospective role(s) for interactions between SUMOylation and Akt serine-phosphorylation during oocyte meiotic resumption. Pharmacological inhibition of SUMOylation significantly decreased follicular fluid meiosis-activating sterol-induced cell-cycle resumption in oocytes matured in vitro and negatively affected the phosphorylation and nuclear translocation of Akt. Similarly, nuclear localization of cyclin D1, a downstream target of Akt activation, was significantly decreased following SUMOylation inhibition. Together these data show that SUMO and the posttranslational process of SUMOylation are involved in cell-cycle resumption during murine oocyte maturation and exert a regulatory influence on the Akt pathway during germinal vesicle breakdown.

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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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Estramustine phosphate inhibits germinal vesicle breakdown and induces depolymerization of microtubules in mouse oocyte

Reproduction Nutrition Development ◽

10.1051/rnd:19880211 ◽

1988 ◽

Vol 28 (2A) ◽

pp. 319-334 ◽

Cited By ~ 2

Author(s):

Hélène RIME ◽

Catherine JESSUS ◽

R. OZON

Keyword(s):

Germinal Vesicle ◽

Mouse Oocyte ◽

Estramustine Phosphate ◽

Germinal Vesicle Breakdown

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OLA1 is responsible for normal spindle assembly and SAC activation in mouse oocytes

10.7287/peerj.preprints.27837 ◽

2019 ◽

Author(s):

Di Xie ◽

Juan Zhang ◽

JinLi Ding ◽

Jing Yang ◽

Yan Zhang

Keyword(s):

Spindle Assembly Checkpoint ◽

Polar Body ◽

Germinal Vesicle ◽

Spindle Assembly ◽

Mouse Oocyte ◽

Immunofluorescent Staining ◽

Germinal Vesicle Breakdown ◽

Oocyte Meiosis ◽

Polar Body Extrusion ◽

Spread Analysis

Background. OLA1 is a member of the GTPase protein family, unlike other members, it can bind and hydrolyze ATP more efficiently than GTP. OLA1 participates in cell proliferation, oxidative response and tumorigenesis. However, whether OLA1 is also required for oocyte meiosis is still unknown. Methods. In this study, the localization, expression, and functions of OLA1 in the mouse oocyte meiosis were examined. Immunofluorescent and confocal microscopy were used to explore the location pattern of OLA1 in the mouse oocyte. Moreover, nocodazole treatment was used to confirm the spindle-like location of OLA1 during mouse meiosis. Western blot was used to explore the expression pattern of OLA1 in the mouse oocyte. Microinjection of siRNA was used to explore the OLA1 functions in the mouse oocyte meiosis. In addition, chromosome spreading was used to investigate the spindle assembly checkpoint (SAC) activity. Results. Immunoﬂuorescent staining showed that OLA1 evenly distributed in the cytoplasm at germinal vesicle (GV) stage. After meiosis resumption (GVBD), OLA1 co-localized with spindles, which was further identified by nocodazole treatment experiments. Knockdown of OLA1 impaired the germinal vesicle breakdown progression and finally resulted in a lower polar body extrusion rate. Immunofluorescence analysis indicated that knockdown of OLA1 led to abnormal spindle assembly, which was evidenced by multipolar spindles in OLA1-RNAi-oocytes. After 6 h post-GVBD in culture, an increased proportion of oocyte which has precociously entered into anaphase/telephase I (A/TI) was observed in OLA1-knockdown oocytes, suggesting that loss of OLA1 resulted in the premature segregation of homologous chromosomes. In addition, the chromosome spread analysis suggested that OLA1 knockdown induced premature anaphase onset was due to the precocious inactivation of SAC. Taken together, we concluded that OLA1 plays important role in GVBD, spindle assembly and SAC activation maintenance in oocyte meiosis.

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Perfluorononanoic acid impedes mouse oocyte maturation by inducing mitochondrial dysfunction and oxidative stress

10.1101/2021.07.06.451300 ◽

2021 ◽

Author(s):

Xiaofei Jiao ◽

Ning Liu ◽

Yiding Xu ◽

Huanyu Qiao

Keyword(s):

Oxidative Stress ◽

Dna Damage ◽

Oocyte Maturation ◽

Early Stage ◽

Spindle Assembly ◽

Mouse Oocyte ◽

Toxic Effects ◽

Germinal Vesicle Breakdown ◽

Maturation In Vitro

Perfluorononanoic acid (PFNA), a member of PFAS, is frequently detected in human blood and tissues, even in follicular fluid of women. The exposure of PFNA, but not PFOA and PFOS, is positively correlated with miscarriage and increased time to pregnancy. Toxicological studies indicated that PFNA exposure is associated with immunotoxicity, hepatotoxicity, developmental toxicity, and reproductive toxicity in animals. However, there is little information regarding the toxic effects of PFNA on oocyte maturation. In this study, we investigated the toxic effects of PFNA exposure on mouse oocyte maturation in vitro. Our results showed that 600 μM PFNA significantly inhibited germinal vesicle breakdown (GVBD) and polar body extrusion (PBE) in mouse oocytes. Our further study revealed that PFNA induced abnormal metaphase I (MI) spindle assembly, evidenced by malformed spindles and mislocalization of p-ERK1/2 in PFNA-treated oocytes. We also found that PFNA induced abnormal mitochondrial distribution and increased mitochondrial membrane potential. Consequently, PFNA increased reactive oxygen species (ROS) levels, leading to oxidative stress, DNA damage, and eventually early-stage apoptosis in oocytes. In addition, after 14 h culture, PFNA disrupted the formation of metaphase II (MII) spindle in most PFNA-treated oocytes with polar bodies. Collectively, our results indicate that PFNA interferes with oocyte maturation in vitro via disrupting spindle assembly, damaging mitochondrial functions, and inducing oxidative stress, DNA damage, and early-stage apoptosis.

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Insulin-stimulated oocyte maturation requires insulin receptor substrate 1 and interaction with the SH2 domains of phosphatidylinositol 3-kinase

Molecular and Cellular Biology ◽

10.1128/mcb.13.11.6653-6660.1993 ◽

1993 ◽

Vol 13 (11) ◽

pp. 6653-6660

Author(s):

L M Chuang ◽

M G Myers ◽

J M Backer ◽

S E Shoelson ◽

M F White ◽

...

Keyword(s):

Phospholipase C ◽

Oocyte Maturation ◽

Germinal Vesicle ◽

Sh2 Domain ◽

Glutathione S Transferase ◽

Hormonal Stimulation ◽

Germinal Vesicle Breakdown ◽

Sh2 Domains ◽

Igf I ◽

Phospholipase C Gamma

Xenopus oocytes from unprimed frogs possess insulin-like growth factor I (IGF-I) receptors but lack insulin and IGF-I receptor substrate 1 (IRS-1), the endogenous substrate of this kinase, and fail to show downstream responses to hormonal stimulation. Microinjection of recombinant IRS-1 protein enhances insulin-stimulated phosphatidylinositol (PtdIns) 3-kinase activity and restores the germinal vesicle breakdown response. Activation of PtdIns 3-kinase results from formation of a complex between phosphorylated IRS-1 and the p85 subunit of PtdIns 3-kinase. Microinjection of a phosphonopeptide containing a pYMXM motif with high affinity for the src homology 2 (SH2) domain of PtdIns 3-kinase p85 inhibits IRS-1 association with and activation of the PtdIns 3-kinase. Formation of the IRS-1-PtdIns 3-kinase complex and insulin-stimulated PtdIns 3-kinase activation are also inhibited by microinjection of a glutathione S-transferase fusion protein containing the SH2 domain of p85. This effect occurs in a concentration-dependent fashion and results in a parallel loss of hormone-stimulated oocyte maturation. These inhibitory effects are specific and are not mimicked by glutathione S-transferase fusion proteins expressing the SH2 domains of ras-GAP or phospholipase C gamma. Moreover, injection of the SH2 domains of p85, ras-GAP, and phospholipase C gamma do not interfere with progesterone-induced oocyte maturation. These data demonstrate that phosphorylation of IRS-1 plays an essential role in IGF-I and insulin signaling in oocyte maturation and that this effect occurs through interactions of the phosphorylated YMXM/YXXM motifs of IRS-1 with SH2 domains of PtdIns 3-kinase or some related molecules.

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Ha-rasVal-12,Thr-59 activates S6 kinase and p34cdc2 kinase in Xenopus oocytes: evidence for c-mosxe-dependent and -independent pathways

Molecular and Cellular Biology ◽

10.1128/mcb.10.1.310-315.1990 ◽

1990 ◽

Vol 10 (1) ◽

pp. 310-315

Author(s):

C B Barrett ◽

R M Schroetke ◽

F A Van der Hoorn ◽

S K Nordeen ◽

J L Maller

Keyword(s):

Protein Kinase ◽

Oocyte Maturation ◽

Antisense Oligonucleotides ◽

Xenopus Oocytes ◽

Germinal Vesicle ◽

Protein Product ◽

Germinal Vesicle Breakdown ◽

S6 Kinase ◽

Kinase Activation ◽

Histone Kinase

Treatment with insulin or progesterone or microinjection of the transforming protein product of Ha-rasVal-12,Thr-59 (p21) is known to induce germinal vesicle breakdown in Xenopus oocytes. We have investigated the effect of p21 on S6 kinase and the H1 histone kinase of maturation-promoting factor in the presence and absence of antisense oligonucleotides against the c-mosxe proto-oncogene. Injection of p21 led to a rapid increase in S6 phosphorylation, with kinetics similar to those previously observed with insulin. Microinjection of c-mosxe antisense oligonucleotides inhibited germinal vesicle breakdown induced by p21 and totally abolished S6 kinase activation by insulin or progesterone but only partially inhibited activation by p21. However, the activation of p34cdc2 protein kinase by all three stimuli was blocked by antisense oligonucleotides. The results suggest that in oocyte maturation c-mosxe functions downstream of p21 but upstream of p34cdc2 and S6 kinase activation, although not all p21-induced events require c-mosxe.

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