Microtubule Organizing Centers Regulate Spindle Positioning in Mouse Oocytes

2021 ◽  
Author(s):  
Daniela Londono Vasquez ◽  
Katherine Rodriguez-Lukey ◽  
Susanta Behura ◽  
Ahmed Balboula
Keyword(s):  
Spindle Positioning ◽  
Microtubule Organizing Centers ◽  
Mouse Oocytes

Microtubule organizing centers regulate spindle positioning in mouse oocytes

2022 ◽  
Author(s):  
Daniela Londoño-Vásquez ◽  
Katherine Rodriguez-Lukey ◽  
Susanta K. Behura ◽  
Ahmed Z. Balboula
Keyword(s):  
Spindle Positioning ◽  
Microtubule Organizing Centers ◽  
Mouse Oocytes

scholarly journals A New Model for Asymmetric Spindle Positioning in Mouse Oocytes

2008 ◽  
Vol 18 (24) ◽  
pp. 1986-1992 ◽  
Author(s):  
Melina Schuh ◽  
Jan Ellenberg
Keyword(s):  
Spindle Positioning ◽  
New Model ◽  
Mouse Oocytes

scholarly journals Brefeldin A disrupts asymmetric spindle positioning in mouse oocytes

2008 ◽  
Vol 313 (1) ◽  
pp. 155-166 ◽  
Author(s):  
Ling Wang ◽  
Zhen-Bo Wang ◽  
Xuan Zhang ◽  
Greg FitzHarris ◽  
Jay M. Baltz ◽  
...  
Keyword(s):  
Brefeldin A ◽  
Spindle Positioning ◽  
Mouse Oocytes

scholarly journals Spindle assembly in the absence of chromosomes in mouse oocytes

Reproduction ◽  
2007 ◽  
Vol 134 (6) ◽  
pp. 731-738 ◽  
Author(s):  
Ji-Wen Yang ◽  
Zi-Li Lei ◽  
Yi-Liang Miao ◽  
Jun-Cheng Huang ◽  
Li-Hong Shi ◽  
...  
Keyword(s):  
Germinal Vesicle ◽  
Spindle Assembly ◽  
Meiotic Maturation ◽  
Bipolar Spindle ◽  
Microtubule Organizing Centers ◽  
Mouse Oocytes ◽  
Inactive Form ◽  
Different Shapes ◽  
Metaphase I

This study was carried out to investigate the contributions of chromosomes to spindle assembly in mouse oocytes. We generated two groups of cytoplasts (holo- and hemi-cytoplasts) by enucleation of germinal vesicle (GV), metaphase I (MI), and metaphase II (MII) oocytes using micromanipulation technology. After in vitro culture for 18 h, spindles with different shapes (bi-, mono-, or multipolar) formed in most of these cytoplasts except in hemi-GV cytoplasts. Two or more spindles were observed in most of holo-GV, holo-MI, and holo-MII cytoplasts (76.1, 77.0, and 83.7% respectively). However, the proportions of hemi-MI and hemi-MII cytoplasts with multiple sets of spindles decreased to 17.6 and 20.7% respectively. A single bipolar spindle was observed in each sham-operated oocyte generated by removing different volumes of cytoplasm from the oocytes and keeping nuclei intact. Localization of γ-tubulin showed that microtubule organizing centers (MTOCs) were dispersed at each pole of the multiple sets of spindles formed in holo-cytoplasts. However, most of the MTOCs aggregated at the two poles of the bipolar spindle in sham-operated oocytes. Our results demonstrate that chromosomes are not essential for initiating spindle assembly but for directing distinct MTOCs to aggregate to form a bipolar spindle. Some factors of undetermined nature may pre-exist in an inactive form in GV-stage ooplasm, serving as initiators of spindle assembly upon their activation. Moreover, GV materials released into the cytoplasm may facilitate spindle assembly in normal meiotic maturation.

scholarly journals Specific deletion of Cdc42 does not affect meiotic spindle organization/migration and homologous chromosome segregation but disrupts polarity establishment and cytokinesis in mouse oocytes

2013 ◽  
Vol 24 (24) ◽  
pp. 3832-3841 ◽  
Author(s):  
Zhen-Bo Wang ◽  
Zong-Zhe Jiang ◽  
Qing-Hua Zhang ◽  
Meng-Wen Hu ◽  
Lin Huang ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Homologous Chromosome ◽  
Polar Body ◽  
Conditional Knockout ◽  
Meiotic Spindle ◽  
Spindle Positioning ◽  
Mouse Oocytes ◽  
Polar Bodies ◽  
And Migration ◽  
Specific Deletion

Mammalian oocyte maturation is distinguished by highly asymmetric meiotic divisions during which a haploid female gamete is produced and almost all the cytoplasm is maintained in the egg for embryo development. Actin-dependent meiosis I spindle positioning to the cortex induces the formation of a polarized actin cap and oocyte polarity, and it determines asymmetric divisions resulting in two polar bodies. Here we investigate the functions of Cdc42 in oocyte meiotic maturation by oocyte-specific deletion of Cdc42 through Cre-loxP conditional knockout technology. We find that Cdc42 deletion causes female infertility in mice. Cdc42 deletion has little effect on meiotic spindle organization and migration to the cortex but inhibits polar body emission, although homologous chromosome segregation occurs. The failure of cytokinesis is due to the loss of polarized Arp2/3 accumulation and actin cap formation; thus the defective contract ring. In addition, we correlate active Cdc42 dynamics with its function during polar body emission and find a relationship between Cdc42 and polarity, as well as polar body emission, in mouse oocytes.

A soft cortex is essential for asymmetric spindle positioning in mouse oocytes

2013 ◽  
Vol 15 (8) ◽  
pp. 958-966 ◽  
Author(s):  
Agathe Chaigne ◽  
Clément Campillo ◽  
Nir S. Gov ◽  
Raphaël Voituriez ◽  
Jessica Azoury ◽  
...  
Keyword(s):  
Spindle Positioning ◽  
Mouse Oocytes

MAP Kinase Becomes Stably Activated at Metaphase and Is Associated with Microtubule-Organizing Centers during Meiotic Maturation of Mouse Oocytes

1993 ◽  
Vol 158 (2) ◽  
pp. 330-340 ◽  
Author(s):  
Marie-Hélène Verlhac ◽  
Henri de Pennart ◽  
Bernard Maro ◽  
Melanie H. Cobb ◽  
Hugh J. Clarke
Keyword(s):  
Map Kinase ◽  
Meiotic Maturation ◽  
Microtubule Organizing Centers ◽  
Mouse Oocytes

scholarly journals Spindle Positioning in Mouse Oocytes Relies on a Dynamic Meshwork of Actin Filaments

2008 ◽  
Vol 18 (19) ◽  
pp. 1514-1519 ◽  
Author(s):  
Jessica Azoury ◽  
Karen W. Lee ◽  
Virginie Georget ◽  
Pascale Rassinier ◽  
Benjamin Leader ◽  
...  
Keyword(s):  
Actin Filaments ◽  
Spindle Positioning ◽  
Mouse Oocytes

Regulation of spontaneous and induced resumption of meiosis in mouse oocytes by different intracellular pathways

Reproduction ◽  
2000 ◽  
pp. 377-383 ◽  
Author(s):  
L Leonardsen ◽  
A Wiersma ◽  
M Baltsen ◽  
AG Byskov ◽  
CY Andersen
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Mitogen Activated Protein Kinase ◽  
Meiotic Maturation ◽  
Mouse Oocytes ◽  
Mitogen Activated Protein ◽  
Dependent Signal ◽  
Kinase Pathway ◽  
Kinase A

The mitogen-activated protein kinase-dependent and the cAMP-protein kinase A-dependent signal transduction pathways were studied in cultured mouse oocytes during induced and spontaneous meiotic maturation. The role of the mitogen-activated protein kinase pathway was assessed using PD98059, which specifically inhibits mitogen-activated protein kinase 1 and 2 (that is, MEK1 and MEK2), which activates mitogen-activated protein kinase. The cAMP-dependent protein kinase was studied by treating oocytes with the protein kinase A inhibitor rp-cAMP. Inhibition of the mitogen-activated protein kinase pathway by PD98059 (25 micromol l(-1)) selectively inhibited the stimulatory effect on meiotic maturation by FSH and meiosis-activating sterol (that is, 4,4-dimethyl-5alpha-cholest-8,14, 24-triene-3beta-ol) in the presence of 4 mmol hypoxanthine l(-1), whereas spontaneous maturation in the absence of hypoxanthine was unaffected. This finding indicates that different signal transduction mechanisms are involved in induced and spontaneous maturation. The protein kinase A inhibitor rp-cAMP induced meiotic maturation in the presence of 4 mmol hypoxanthine l(-1), an effect that was additive to the maturation-promoting effect of FSH and meiosis-activating sterol, indicating that induced maturation also uses the cAMP-protein kinase A-dependent signal transduction pathway. In conclusion, induced and spontaneous maturation of mouse oocytes appear to use different signal transduction pathways.

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