scholarly journals Inducible nitric oxide synthase-derived nitric oxide regulates germinal vesicle breakdown and first polar body emission in the mouse oocyte

Reproduction ◽  
2005 ◽  
Vol 129 (4) ◽  
pp. 403-409 ◽  
Author(s):  
Li-Jun Huo ◽  
Cheng-Guang Liang ◽  
Ling-Zhu Yu ◽  
Zhi-Sheng Zhong ◽  
Zeng-Ming Yang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Polar Body ◽  
Specific Inhibitor ◽  
Germinal Vesicle ◽  
Mouse Oocyte ◽  
Germinal Vesicle Breakdown ◽  
First Polar Body ◽  
Oxide Synthase ◽  
Oocyte Meiotic Maturation ◽  
Inducible Nitric Oxide

The present study investigated the subcellular localization of inducible nitric oxide synthase (iNOS) during mouse oocyte meiotic maturation and fertilization using confocal microscopy, and further studied the roles of iNOS-derived NO in oocyte maturation by using an iNOS-specific inhibitor aminoguanidine (AG) and iNOS antibody microinjection. In germinal vesicle-stage oocytes, iNOS immunoreactivity was mainly localized in the germinal vesicle. Shortly after germinal vesicle breakdown, the iNOS immunoreactivity accumulated around the condensed chromosomes. At metaphase I and metaphase II, with the organization of chromosomes to the equatorial plate, iNOS immunoreactivity was concentrated around the aligned chromosomes, putatively the position of the metaphase spindle. The accumulation of iNOS immunoreactivity could not be detected at anaphase I and anaphase II. However, at telophase I and telophase II, the staining of iNOS was concentrated in the region between the separating chromosomes/chromatids. Furthermore, the staining of iNOS also accumulated in the male and female pronuclei in fertilized eggs. Germinal vesicle breakdown and the first polar body emission of the oocytes were significantly blocked by the iNOS-specific inhibitor AG in a dose-dependent manner. The germinal vesicle breakdown in oocytes injected with iNOS antibody was also inhibited. We found that the phosphorylation of mitogen-activated protein kinase in oocytes after germinal vesicle breakdown was inhibited by AG treatment. The control oocytes extruded a normal first polar body, while the AG-treated oocytes exhibited an elongated protrusion or no elongated protrusion. The results of confocal microscopy showed that the AG-treated oocytes were arrested at anaphase I–telophase I. Our results suggest that the iNOS-derived NO pathway plays important roles in mouse oocyte meiotic maturation, especially in germinal vesicle breakdown and the anaphase–telophase transition.

JNK2 Participates in Spindle Assembly during Mouse Oocyte Meiotic Maturation

2011 ◽  
Vol 17 (2) ◽  
pp. 197-205 ◽  
Author(s):  
Xin Huang ◽  
Jing-Shan Tong ◽  
Zhen-Bo Wang ◽  
Cai-Rong Yang ◽  
Shu-Tao Qi ◽  
...  
Keyword(s):  
Polar Body ◽  
Specific Inhibitor ◽  
Germinal Vesicle ◽  
Spindle Assembly ◽  
Mouse Oocyte ◽  
Meiotic Maturation ◽  
Cytoplasmic Microtubule ◽  
Spindle Poles ◽  
First Polar Body ◽  
Oocyte Meiotic Maturation

AbstractIt is well known that c-Jun N-terminal kinase (JNK) plays pivotal roles in various mitotic events, but its function in mammalian oocyte meiosis remains unknown. In this study, we found that no specific JNK2 signal was detected in germinal vesicle stage. JNK2 was associated with the spindles especially the spindle poles and cytoplasmic microtubule organizing centers at prometaphase I, metaphase I, and metaphase II stages. JNK2 became diffusely distributed and associated with the midbody at telophase I stage. Injection of myc-tagged JNK2α1 mRNA into oocytes also revealed its localization on spindle poles. The association of JNK2 with spindle poles was further confirmed by colocalization with the centrosomal proteins, γ-tubulin and Plk1. Nocodazole treatment showed that JNK2 may interact with Plk1 to regulate the spindle assembly. Then we investigated the possible function of JNK2 by JNK2 antibody microinjection and JNK specific inhibitor SP600125 treatment. These two manipulations caused abnormal spindle formation and decreased the rate of first polar body (PB1) extrusion. In addition, inhibition of JNK2 resulted in impaired localization of Plk1. Taken together, our results suggest that JNK2 plays an important role in spindle assembly and PB1 extrusion during mouse oocyte meiotic maturation.

The Distribution and Possible Role of ERK8 in Mouse Oocyte Meiotic Maturation and Early Embryo Cleavage

2013 ◽  
Vol 19 (1) ◽  
pp. 190-200 ◽  
Author(s):  
Shang-Wu Yang ◽  
Hao Huang ◽  
Chen Gao ◽  
Lei Chen ◽  
Shu-Tao Qi ◽  
...  
Keyword(s):  
Polar Body ◽  
Germinal Vesicle ◽  
Early Embryo ◽  
Mouse Oocyte ◽  
Meiotic Maturation ◽  
Germinal Vesicle Breakdown ◽  
First Polar Body ◽  
Embryo Cleavage ◽  
Polar Body Extrusion ◽  
Oocyte Meiotic Maturation

AbstractIt is well known that extracellular signal-regulated kinase 8 (ERK8) plays pivotal roles in various mitotic events. But its physiological roles in oocyte meiotic maturation remain unclear. In this study, we found that although no specific ERK8 signal was detected in oocyte at the germinal vesicle stage, ERK8 began to migrate to the periphery of chromosomes shortly after germinal vesicle breakdown. At prometaphase I, metaphase I (MI), anaphase I, telophase I, and metaphase II (MII) stages, ERK8 was stably detected at the spindles. By taxol treatment, we clarified that the ERK8 signal was stained on the spindle fibers as well as microtubule asters in MI and MII oocytes. In fertilized eggs, the ERK8 signal was not observed in the two pronuclei stages. At prometaphase, metaphase, and anaphase of the first mitosis, ERK8 was detected on the mitotic spindle. ERK8 knock down by antibody microinjection and specific siRNA caused abnormal spindles, failed chromosome congression, and decreased first polar body extrusion. Taken together, our results suggest that ERK8 plays an important role in spindle organization during mouse oocyte meiotic maturation and early embryo cleavage.

scholarly journals Translocation of phospho-protein kinase Cs implies their roles in meiotic-spindle organization, polar-body emission and nuclear activity in mouse eggs

Reproduction ◽  
2005 ◽  
Vol 129 (2) ◽  
pp. 229-234 ◽  
Author(s):  
Zhen-Yu Zheng ◽  
Qing-Zhang Li ◽  
Da-Yuan Chen ◽  
Heide Schatten ◽  
Qing-Yuan Sun
Keyword(s):  
Protein Kinase ◽  
Polar Body ◽  
Germinal Vesicle ◽  
Mouse Oocyte ◽  
Meiotic Spindle ◽  
Germinal Vesicle Breakdown ◽  
Nuclear Activity ◽  
Spindle Poles ◽  
Oocyte Meiosis ◽  
First Polar Body

The protein kinase Cs (PKCs) are a family of Ser/Thr protein kinases categorized into three subfamilies: classical, novel, and atypical. The phosphorylation of PKC in germ cells is not well defined. In this study, we described the subcellular localization of phopho-PKC in the process of mouse oocyte maturation, fertilization, and early embryonic mitosis. Confocal microscopy revealed that phospho-PKC (pan) was distributed abundantly in the nucleus at the germinal vesicle stage. After germinal vesicle breakdown, phospho-PKC was localized in the vicinity of the condensed chromosomes, distributed in the whole meiotic spindle, and concentrated at the spindle poles. After metaphase I, phospho-PKC was translocated gradually to the spindle mid-zone during emission of the first polar body. After sperm penetration and electrical activation, the distribution of phospho-PKC was moved from the spindle poles to the spindle mid-zone. After the extrusion of the second polar body (PB2) phospho-PKC was localized in the area between the oocyte and the PB2. In fertilized eggs, phospho-PKC was concentrated in the pronuclei except for the nucleolus. Phospho-PKC was dispersed after pronuclear envelope breakdown, but distributed on the entire spindle at mitotic metaphase. The results suggest that PKC activation may play important roles in regulating spindle organization and stabilization, polar-body extrusion, and nuclear activity during mouse oocyte meiosis, fertilization, and early embryonic mitosis.

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

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.

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

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.

Involvement of GABAA receptor in Bufo arenarum oocyte maturation

Zygote ◽  
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.

scholarly journals Glycogen synthase kinase 3B in bovine oocytes and granulosa cells: possible involvement in meiosis during in vitro maturation

Reproduction ◽  
2009 ◽  
Vol 138 (2) ◽  
pp. 235-246 ◽  
Author(s):  
Svetlana Uzbekova ◽  
Mohamad Salhab ◽  
Christine Perreau ◽  
Pascal Mermillod ◽  
Joëlle Dupont
Keyword(s):  
Granulosa Cells ◽  
Map Kinases ◽  
Glycogen Synthase ◽  
Polar Body ◽  
Germinal Vesicle ◽  
Glycogen Synthase Kinase ◽  
Aurora A Kinase ◽  
Germinal Vesicle Breakdown ◽  
First Polar Body

Glycogen synthase kinase 3 (GSK3) regulates cellular metabolism and cell cycle via different signalling pathways. In response to insulin and growth factors GSK3 is serine-phosphorylated and inactivated. We analysed GSK3B expression and activation in bovine cumulus cells (CC) and oocytes at different meiotic stagesin vitroin parallel with MAP kinases ERK (MAPK3/MAPK1) and p38 (MAPK14). GSK3B localised to cytoplasm in granulosa cells and in oocytes throughout folliculogenesis. In mature metaphase-II (MII) oocytes, GSK3B was concentrated to the region of midzone between the oocyte and the first polar body, as well as active phospho-Thr Aurora A kinase (AURKA). Duringin vitromaturation (IVM), in oocytes, phospho-Ser9-GSK3B level increased as well as phospho-MAPK3/MAPK1, while phospho-MAPK14 decreased. In CC, phospho-MAPK14 increased upon germinal vesicle breakdown (GVBD)/metaphase-I (MI) and then decreased during transition to MII. Administration of inhibitors of GSK3 activity (lithium chloride or 2′Z,3′E -6-bromoindirubin-3′-oxime) rapidly increased phospho-Ser9-GSK3B, and led to transient decrease of phospho-MAPK3/MAPK1 and to durable enhancing of phospho-MAPK14 in granulosa primary cell culture. GSK3 inhibitors during IVM diminished cumulus expansion and delayed meiotic progression. In cumulus, phospho-MAPK14 level was significantly higher in the presence of inhibitors, comparing with control, through the time of MI/MII transition. In oocytes, phospho-GSK3B was increased and phospho-MAPK3/MAPK1 was decreased before GVBD and oocytes were mainly arrested at MI. Therefore, GSK3B might regulate oocyte meiosis, notably MI/MII transition being the part of MAPK3/1 and MAPK14 pathways in oocytes and CC. GSK3B might be also involved in the local activation of AURKA that controls this transition.

scholarly journals NAT10-Mediated N4-Acetylcytidine of RNA Contributes to Post-transcriptional Regulation of Mouse Oocyte Maturation in vitro

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuting Xiang ◽  
Chuanchuan Zhou ◽  
Yanyan Zeng ◽  
Qi Guo ◽  
Jiana Huang ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
High Throughput Sequencing ◽  
Epigenetic Modification ◽  
Binding Protein ◽  
Polar Body ◽  
Germinal Vesicle ◽  
Translation Efficiency ◽  
Germinal Vesicle Breakdown ◽  
First Polar Body

N4-acetylcytidine (ac4C), a newly identified epigenetic modification within mRNA, has been characterized as a crucial regulator of mRNA stability and translation efficiency. However, the role of ac4C during oocyte maturation, the process mainly controlled via post-transcriptional mechanisms, has not been explored. N-acetyltransferase 10 (NAT10) is the only known enzyme responsible for ac4C production in mammals and ac4C-binding proteins have not been reported yet. In this study, we have documented decreasing trends of both ac4C and NAT10 expression from immature to mature mouse oocytes. With NAT10 knockdown mediated by small interfering RNA (siRNA) in germinal vesicle (GV)-stage oocytes, ac4C modification was reduced and meiotic maturation in vitro was significantly retarded. Specifically, the rate of first polar body extrusion was significantly decreased with NAT10 knockdown (34.6%) compared to control oocytes without transfection (74.6%) and oocytes transfected with negative control siRNA (72.6%) (p < 0.001), while rates of germinal vesicle breakdown (GVBD) were not significantly different (p = 0.6531). RNA immunoprecipitation and high-throughput sequencing using HEK293T cells revealed that the modulated genes were enriched in biological processes associated with nucleosome assembly, chromatin silencing, chromatin modification and cytoskeletal anchoring. In addition, we identified TBL3 as a potential ac4C-binding protein by a bioinformatics algorithm and RNA pulldown with HEK293T cells, which may mediate downstream cellular activities. Taken together, our results suggest that NAT10-mediated ac4C modification is an important regulatory factor during oocyte maturation in vitro and TBL3 is a potential ac4C-binding protein.

Thioglycolic acid inhibits mouse oocyte maturation and affects chromosomal arrangement and spindle configuration

2008 ◽  
Vol 24 (4) ◽  
pp. 227-234 ◽  
Author(s):  
SY Hou ◽  
L Zhang ◽  
K Wu ◽  
L Xia
Keyword(s):  
Thioglycolic Acid ◽  
Polar Body ◽  
Germinal Vesicle ◽  
Germinal Vesicle Breakdown ◽  
Chromosomal Arrangement ◽  
First Polar Body ◽  
Inverted Microscope ◽  
Polar Body Formation ◽  
Spindle Elongation

Previous studies have shown that thioglycolic acid (TGA) leads to potential reproductive toxicology. To clarify the exact effects of this compound on reproduction, mice oocytes were treated with different TGA doses. At the end of the culture period, the nuclear status of mice oocytes was assessed under an inverted microscope. After immunofluorescence staining, the chromosomal arrangement and spindle configuration of oocytes were evaluated. The results indicated that TGA decreases the percentage of first polar body formation but does not influence that of germinal vesicle breakdown. TGA induces abnormal chromosomal arrangement and spindle elongation. In conclusion, TGA inhibits in-vitro maturation of mice oocytes and affects chromosomal arrangement and spindle configuration. Furthermore, it probably interferes with biochemical changes that occur during meiosis, resulting in aberrant development.

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