scholarly journals WASH complex regulates Arp2/3 complex for actin-based polar body extrusion in mouse oocytes

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Fei Wang ◽  
Liang Zhang ◽  
Guang-Li Zhang ◽  
Zhen-Bo Wang ◽  
Xiang-Shun Cui ◽  
...  
Keyword(s):  
Polar Body ◽  
Mouse Oocytes ◽  
Polar Body Extrusion

scholarly journals Ral GTPase is essential for actin dynamics and Golgi apparatus distribution in mouse oocyte maturation

Cell Division ◽  
2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ming-Hong Sun ◽  
Lin-Lin Hu ◽  
Chao-Ying Zhao ◽  
Xiang Lu ◽  
Yan-Ping Ren ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
Oocyte Maturation ◽  
Polar Body ◽  
Mouse Oocyte ◽  
Actin Dynamics ◽  
Mouse Oocytes ◽  
Oocyte Meiosis ◽  
Ral Gtpase ◽  
Polar Body Extrusion ◽  
Cytoskeleton Dynamics

Abstract Background Ral family is a member of Ras-like GTPase superfamily, which includes RalA and RalB. RalA/B play important roles in many cell biological functions, including cytoskeleton dynamics, cell division, membrane transport, gene expression and signal transduction. However, whether RalA/B involve into the mammalian oocyte meiosis is still unclear. This study aimed to explore the roles of RalA/B during mouse oocyte maturation. Results Our results showed that RalA/B expressed at all stages of oocyte maturation, and they were enriched at the spindle periphery area after meiosis resumption. The injection of RalA/B siRNAs into the oocytes significantly disturbed the polar body extrusion, indicating the essential roles of RalA/B for oocyte maturation. We observed that in the RalA/B knockdown oocytes the actin filament fluorescence intensity was significantly increased at the both cortex and cytoplasm, and the chromosomes were failed to locate near the cortex, indicating that RalA/B regulate actin dynamics for spindle migration in mouse oocytes. Moreover, we also found that the Golgi apparatus distribution at the spindle periphery was disturbed after RalA/B depletion. Conclusions In summary, our results indicated that RalA/B affect actin dynamics for chromosome positioning and Golgi apparatus distribution in mouse oocytes.

scholarly journals Kinetochore Fibers Are Not Involved in the Formation of the First Meiotic Spindle in Mouse Oocytes, but Control the Exit from the First Meiotic M Phase

1999 ◽  
Vol 146 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Stéphane Brunet ◽  
Angélica Santa Maria ◽  
Philippe Guillaud ◽  
Denis Dujardin ◽  
Jacek Z. Kubiak ◽  
...  
Keyword(s):  
Polar Body ◽  
Meiotic Spindle ◽  
Homologous Chromosomes ◽  
Mouse Oocytes ◽  
Sister Chromatids ◽  
M Phase ◽  
Continuous Presence ◽  
Set Up ◽  
Polar Body Extrusion ◽  
Reductional Division

During meiosis, two successive divisions occur without any intermediate S phase to produce haploid gametes. The first meiotic division is unique in that homologous chromosomes are segregated while the cohesion between sister chromatids is maintained, resulting in a reductional division. Moreover, the duration of the first meiotic M phase is usually prolonged when compared with mitotic M phases lasting 8 h in mouse oocytes. We investigated the spindle assembly pathway and its role in the progression of the first meiotic M phase in mouse oocytes. During the first 4 h, a bipolar spindle forms and the chromosomes congress near the equatorial plane of the spindle without stable kinetochore– microtubule end interactions. This late prometaphase spindle is then maintained for 4 h with chromosomes oscillating in the central region of the spindle. The kinetochore–microtubule end interactions are set up at the end of the first meiotic M phase (8 h after entry into M phase). This event allows the final alignment of the chromosomes and exit from metaphase. The continuous presence of the prometaphase spindle is not required for progression of the first meiotic M phase. Finally, the ability of kinetochores to interact with microtubules is acquired at the end of the first meiotic M phase and determines the timing of polar body extrusion.

scholarly journals Cell cycle modification during the transitions between meiotic M-phases in mouse oocytes

1992 ◽  
Vol 102 (3) ◽  
pp. 457-467 ◽  
Author(s):  
J.Z. Kubiak ◽  
M. Weber ◽  
G. Geraud ◽  
B. Maro
Keyword(s):  
Kinase Activity ◽  
Polar Body ◽  
Metaphase Arrest ◽  
Phosphorylated Proteins ◽  
Mouse Oocytes ◽  
Sequence Of Events ◽  
M Phase ◽  
Second Polar Body ◽  
Polar Body Extrusion ◽  
Centrosomal Proteins

When metaphase II-arrested mouse oocytes (M II) are activated very soon after ovulation, they respond abortively by second polar body extrusion followed by another metaphase arrest (metaphase III, M III; Kubiak, 1989). The M II/M III transition resembles the natural transition between the first and second meiotic metaphases (M I/M II). We observed that a similar sequence of events takes place during these two transitions: after anaphase, a polar body is extruded, the microtubules of the midbody disappear rapidly and a new metaphase spindle forms. The MPM-2 monoclonal antibody (which reacts with phosphorylated proteins associated with the centrosome during M-phase) stains discrete foci of peri-centriolar material only in metaphase arrested oocytes; during both transitional periods, a diffuse staining is observed, suggesting that these centrosomal proteins are dephosphorylated, as in a normal interphase. However, the chromosomes always remain condensed and an interphase network of microtubules is never observed during the transitional periods. Incorporation of 32P into proteins increases specifically during the transitional periods. Pulse-chase experiments, after labeling of the oocytes in M phase with 32P, showed that a 62 kDa phosphoprotein band disappears at the time of polar body extrusion. Histone H1 kinase activity (which reflects the activity of the maturation promoting factor) drops during both transitional periods to the level characteristic of interphase and then increases when the new spindle forms. Both the M I/M II and M II/M III transitions require protein synthesis as demonstrated by the effect of puromycin. These results suggest that the two M-phase/M-phase transitions are probably driven by the same molecular mechanism.

Inhibition of protein kinases by 6-dimethylaminopurine accelerates the transition to interphase in activated mouse oocytes

1993 ◽  
Vol 104 (3) ◽  
pp. 861-872 ◽  
Author(s):  
M.S. Szollosi ◽  
J.Z. Kubiak ◽  
P. Debey ◽  
H. de Pennart ◽  
D. Szollosi ◽  
...  
Keyword(s):  
Protein Phosphorylation ◽  
Kinase Inhibitor ◽  
Polar Body ◽  
Histone H1 ◽  
Sperm Chromatin ◽  
Oocyte Activation ◽  
Mouse Oocytes ◽  
Spindle Rotation ◽  
Polar Body Extrusion ◽  
Pronuclear Formation

Mouse oocyte activation is followed by a peculiar period during which the interphase network of microtubules does not form and the chromosomes remain condensed despite the inactivation of MPF. To evaluate the role of protein phosphorylation during this period, we studied the effects of the protein kinase inhibitor 6-dimethylaminopurine (6-DMAP) on fertilization and/or parthenogenetic activation of metaphase II-arrested mouse oocytes. 6-DMAP by itself does not induce the inactivation of histone H1 kinase in metaphase II-arrested oocytes, and does not influence the dynamics of histone H1 kinase inactivation during oocyte activation. However, 6-DMAP inhibits protein phosphorylation after oocyte activation. In addition, the phosphorylated form of some proteins disappear earlier in oocytes activated in the presence of 6-DMAP than in the activated control oocytes. This is correlated with the acceleration of some post-fertilization morphological events, such as sperm chromatin decondensation and its transient recondensation, formation of the interphase network of microtubules and pronuclear formation. In addition, numerous abnormalities could be observed: (1) the spindle rotation and polar body extrusion are inhibited; (2) the exchange of protamines into histones seems to be impaired, as judged by the morphology of DNA fibrils by electron microscopy; (3) the formation of a new nuclear envelope around the sperm chromatin proceeds prematurely, while recondensation is not yet completed. These observations suggest that the 6-DMAP-sensitive kinase(s) is (are) involved in the control of post-fertilization events such as the formation of the interphase network of microtubules, the remodelling of sperm chromatin and pronucleus formation.

scholarly journals The Ran GTPase Mediates Chromatin Signaling to Control Cortical Polarity during Polar Body Extrusion in Mouse Oocytes

2007 ◽  
Vol 12 (2) ◽  
pp. 301-308 ◽  
Author(s):  
Manqi Deng ◽  
Praveen Suraneni ◽  
Richard M. Schultz ◽  
Rong Li
Keyword(s):  
Polar Body ◽  
Ran Gtpase ◽  
Mouse Oocytes ◽  
Polar Body Extrusion

124. THE ROLE OF CALCIUM ACTIVATED CHLORIDE CHANNELS AT FERTILISATION

2010 ◽  
Vol 22 (9) ◽  
pp. 42
Author(s):  
S. Dalati ◽  
M. L. Day
Keyword(s):  
Chloride Channels ◽  
Polar Body ◽  
Signal Transduction Pathway ◽  
Active Role ◽  
Niflumic Acid ◽  
In Vitro Fertilisation ◽  
Mouse Oocytes ◽  
Cl Channel ◽  
Polar Body Extrusion

Sperm entry into the oocyte triggers a signal transduction pathway resulting in intracellular calcium [Ca2+] oscillations that coincide with hyperpolarisations in membrane potential (Em). Ca2+ oscillations have been previously described and found to be important for embryo development, yet Em hyperpolarisations and their importance at fertilisation still remains unclear. Thimerosal, a sulfhydryl reagent, has been shown to mimic the physiological changes caused by sperm following fertilisation. It does this by direct sensitisation of the inositol 1,4,5-triphosphate receptor-1 to basal levels of inositol 1,4,5-triphopshate. Previous patch clamp analysis of unfertilised mouse oocytes has shown that thimerosal elicits simultaneous Em hyperpolarisations and Ca2+ oscillations. These results have lead us to hypothesise that hyperpolarisations in Em may be due to the activation of a Ca2+ activated Cl- channel (CaCC) present in the membrane of mouse oocytes. The present study aims to identify this CaCC and assess its role in early development following fertilisation. Hyperpolarisations induced by thimerosal were inhibited by niflumic acid, a selective blocker of CaCCs. The inhibition of Em hyperpolarisations suggests that a CaCC is present and plays an active role in initiating hyperpolarisations. To identify the function of the CaCC at fertilisation, in vitro fertilisation was performed in the presence of niflumic acid. Niflumic acid inhibited polar body extrusion and pronuclei formation; two events that are indicators of fertilisation. Furthermore, Ca2+ imaging experiments with the calcium sensitive dye fura 2-AM, demonstrated that in the presence of niflumic acid, Ca2+ oscillations induced by thimerosal are reduced in size, number and duration. Taken together these data suggest that the activation of a Ca2+ activated Cl– channel in the mouse oocyte may play an important role in the events occurring at fertilisation.

Increased frequency of chromosome congression defects and aneuploidy in mouse oocytes cultured at lower temperature

2017 ◽  
Vol 29 (5) ◽  
pp. 968 ◽  
Author(s):  
Jitka Danadova ◽  
Natalie Matijescukova ◽  
Anna Mac Gillavry Danylevska ◽  
Martin Anger
Keyword(s):  
Developmental Disorders ◽  
Incubation Temperature ◽  
Small Deviation ◽  
Polar Body ◽  
Culture Conditions ◽  
Mouse Oocytes ◽  
Chromosome Congression ◽  
Lower Temperature ◽  
Polar Body Extrusion

Optimal culture conditions are essential for successful IVM of mammalian oocytes and for their further development into an embryo. In the present study we used live cell imaging microscopy to assess the effects of suboptimal culture temperature on various aspects of IVM, including duration of meiosis I, dynamics of polar body extrusion, chromosome congression, anaphase-promoting complex/cyclosome (APC/C) activation and aneuploidy. The data showed that even a small deviation from the optimal incubation temperature causes marked changes in the duration and synchronicity of meiosis, APC/C activity and the frequency of chromosome congression and segregation errors. In vitro manipulation and maturation of germ cells is widely used in both human and animal artificial reproduction techniques. Mammalian oocytes are naturally prone to chromosomal segregation errors, which are responsible for severe mental and developmental disorders. The data presented herein demonstrate that exposure of mouse oocytes to suboptimal temperature during manipulation and maturation could further increase the frequency of chromosome segregation defects in these cells.

scholarly journals Comparison of the toxic effects of different mycotoxins on porcine and mouse oocyte meiosis

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5111 ◽  
Author(s):  
Yujie Lu ◽  
Yue Zhang ◽  
Jia-Qian Liu ◽  
Peng Zou ◽  
Lu Jia ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Animal Feed ◽  
Polar Body ◽  
Oocyte Quality ◽  
Mouse Oocyte ◽  
Toxic Effects ◽  
Mouse Oocytes ◽  
Oocyte Meiosis ◽  
Porcine Oocyte ◽  
Polar Body Extrusion

Background Aflatoxin B1 (AFB1), deoxynivalenol (DON), HT-2, ochratoxin A (OTA), zearalenone (ZEA) are the most common mycotoxins that are found in corn-based animal feed which have multiple toxic effects on animals and humans. Previous studies reported that these mycotoxins impaired mammalian oocyte quality. However, the effective concentrations of mycotoxins to animal oocytes were different. Methods In this study we aimed to compare the sensitivity of mouse and porcine oocytes to AFB1, DON, HT-2, OTA, and ZEA for mycotoxin research. We adopted the polar body extrusion rate of mouse and porcine oocyte as the standard for the effects of mycotoxins on oocyte maturation. Results and Discussion Our results showed that 10 μM AFB1 and 1 μM DON significantly affected porcine oocyte maturation compared with 50 μM AFB1 and 2 μM DON on mouse oocytes. However, 10 nM HT-2 significantly affected mouse oocyte maturation compared with 50 nM HT-2 on porcine oocytes. Moreover, 5 μM OTA and 10 μM ZEA significantly affected porcine oocyte maturation compared with 300 μM OTA and 50 μM ZEA on mouse oocytes. In summary, our results showed that porcine oocytes were more sensitive to AFB1, DON, OTA, and ZEA than mouse oocytes except HT-2 toxin.

Capacity of mouse oocytes to become activated depends on completion of cytoplasmic but not nuclear meiotic maturation

Zygote ◽  
1995 ◽  
Vol 3 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Joise M.L. McConnell ◽  
Liz Campbell ◽  
Caroline Vincent
Keyword(s):  
Chromosomal Rearrangements ◽  
Polar Body ◽  
Calcium Ionophore ◽  
Germinal Vesicle ◽  
Calcium Ionophore A23187 ◽  
Meiotic Maturation ◽  
Ionophore A23187 ◽  
Germinal Vesicle Breakdown ◽  
Mouse Oocytes ◽  
Polar Body Extrusion

SummaryThe ability of mouse oocytes to become activated after exposure too the calcium ionophore A23187 has been investigated at different stages of meiotic maturation. The potential to respond to ionophore has been studied in relation to the time since resumption of meiotic maturation, the chromosomal conformation of the DNA within each cell and the protein synthetic profile of the maturing oocyte. Our studies demonstrate that when maturing oocytes from an MF1 strain of mice were treated with A23187 activation occured only in oocytes which had reached second meiotic metaphase (MII). However, development of the ability to respond to ionophore was not dependent on an orderly progression through normal chromosomal rearrangements such as separation at metaphase I (MI) and subsequent polar body extrusion, since there process could be prevented and the capacity to be activated became apparent in such oocytes at a time when control cells had reached MII. These data suggest that the ability to respond to ionophore depends on the development of a cytoplasmic or complex capable of monitoring the time since initiation of germinal vesicle breakdown. Metabolic radiolabelling of oocytes which were able to respond to calcium ionophore, even though they had been prevented from undergoing normal chromosomal rearrangements, showed them to be synthesising a group of proteins known as the 35 kDa complex.

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