scholarly journals Rac Activity Is Polarized and Regulates Meiotic Spindle Stability and Anchoring in Mammalian Oocytes

2007 ◽  
Vol 12 (2) ◽  
pp. 309-317 ◽  
Author(s):  
Guillaume Halet ◽  
John Carroll
Keyword(s):  
Meiotic Spindle ◽  
Spindle Stability

scholarly journals Klp2 and Ase1 synergize to maintain meiotic spindle stability during metaphase I

2020 ◽  
Author(s):  
Fan Zheng ◽  
Fenfen Dong ◽  
Shuo Yu ◽  
Tianpeng Li ◽  
Yanze Jian ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Yeast Cells ◽  
Meiotic Spindle ◽  
Homologous Chromosomes ◽  
Spindle Dynamics ◽  
Live Cell Microscopy ◽  
Spindle Stability ◽  
Cell Microscopy ◽  
Mitosis And Meiosis ◽  
Meiosis I

ABSTRACTThe spindle apparatus segregates bi-oriented sister chromatids during mitosis but mono-oriented homologous chromosomes during meiosis I. It has remained unclear if similar molecular mechanisms operate to regulate spindle dynamics during mitosis and meiosis I. Here, we employed live-cell microscopy to compare the spindle dynamics of mitosis and meiosis I in fission yeast cells and demonstrated that the conserved kinesin-14 motor Klp2 plays a specific role in maintaining metaphase spindle length during meiosis I, but not during mitosis. Moreover, the maintenance of metaphase spindle stability during meiosis I requires the synergism between Klp2 and the conserved microtubule crosslinker Ase1 as the absence of both proteins causes exacerbated defects in metaphase spindle stability. The synergism is not necessary for regulating mitotic spindle dynamics. Hence, our work reveals a new molecular mechanism underlying meiotic spindle dynamics and provides insights into understanding differential regulation of meiotic and mitotic events.

scholarly journals Meiotic spindle stability depends on MAPK-interacting and spindle-stabilizing protein (MISS), a new MAPK substrate

2002 ◽  
Vol 157 (4) ◽  
pp. 603-613 ◽  
Author(s):  
Christophe Lefebvre ◽  
M. Emilie Terret ◽  
Alexandre Djiane ◽  
Pascale Rassinier ◽  
Bernard Maro ◽  
...  
Keyword(s):  
Antisense Rna ◽  
Mapk Pathway ◽  
Meiotic Spindle ◽  
Mitogen Activated Protein Kinases ◽  
Mitogen Activated Protein ◽  
Cytostatic Factor ◽  
Morpholino Oligonucleotides ◽  
Spindle Stability ◽  
Two Hybrid ◽  
Segregation Of Chromosomes

Vertebrate oocytes arrest in the second metaphase of meiosis (metaphase II [MII]) by an activity called cytostatic factor (CSF), with aligned chromosomes and stable spindles. Segregation of chromosomes occurs after fertilization. The Mos/…/MAPK (mitogen-activated protein kinases) pathway mediates this MII arrest. Using a two-hybrid screen, we identified a new MAPK partner from a mouse oocyte cDNA library. This protein is unstable during the first meiotic division and accumulates only in MII, where it localizes to the spindle. It is a substrate of the Mos/…/MAPK pathway. The depletion of endogenous RNA coding for this protein by three different means (antisense RNA, double-stranded [ds] RNA, or morpholino oligonucleotides) induces severe spindle defects specific to MII oocytes. Overexpressing the protein from an RNA not targeted by the morpholino rescues spindle destabilization. However, dsRNA has no effect on the first two mitotic divisions. We therefore have discovered a new MAPK substrate involved in maintaining spindle integrity during the CSF arrest of mouse oocytes, called MISS (for MAP kinase–interacting and spindle-stabilizing protein).

scholarly journals Klp2 and Ase1 synergize to maintain meiotic spindle stability during metaphase I

2020 ◽  
Vol 295 (38) ◽  
pp. 13287-13298
Author(s):  
Fan Zheng ◽  
Fenfen Dong ◽  
Shuo Yu ◽  
Tianpeng Li ◽  
Yanze Jian ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Yeast Cells ◽  
Meiotic Spindle ◽  
Homologous Chromosomes ◽  
Spindle Dynamics ◽  
Live Cell Microscopy ◽  
Spindle Stability ◽  
Cell Microscopy ◽  
Mitosis And Meiosis ◽  
Meiosis I

The spindle apparatus segregates bi-oriented sister chromatids during mitosis but mono-oriented homologous chromosomes during meiosis I. It has remained unclear if similar molecular mechanisms operate to regulate spindle dynamics during mitosis and meiosis I. Here, we employed live-cell microscopy to compare the spindle dynamics of mitosis and meiosis I in fission yeast cells and demonstrated that the conserved kinesin-14 motor Klp2 plays a specific role in maintaining metaphase spindle length during meiosis I but not during mitosis. Moreover, the maintenance of metaphase spindle stability during meiosis I requires the synergism between Klp2 and the conserved microtubule cross-linker Ase1, as the absence of both proteins causes exacerbated defects in metaphase spindle stability. The synergism is not necessary for regulating mitotic spindle dynamics. Hence, our work reveals a new molecular mechanism underlying meiotic spindle dynamics and provides insights into understanding differential regulation of meiotic and mitotic events.

scholarly journals Mechanisms underlying disruption of oocyte spindle stability by bisphenol compounds

Reproduction ◽  
2020 ◽  
Vol 159 (4) ◽  
pp. 383-396 ◽  
Author(s):  
Luhan Yang ◽  
Claudia Baumann ◽  
Rabindranth De La Fuente ◽  
Maria M Viveiros
Keyword(s):  
Aurora Kinase ◽  
Rapid Onset ◽  
Spindle Pole ◽  
Potential Interaction ◽  
Meiotic Spindle ◽  
Dependent Manner ◽  
Aurora Kinase A ◽  
Multipolar Spindles ◽  
Spindle Stability ◽  
Kinase A

Accurate chromosome segregation relies on correct chromosome-microtubule interactions within a stable bipolar spindle apparatus. Thus, exposure to spindle disrupting compounds can impair meiotic division and genomic stability in oocytes. The endocrine disrupting activity of bisphenols such as bisphenol A (BPA) is well recognized, yet their damaging effects on spindle microtubules (MTs) is poorly understood. Here, we tested the effect(s) of acute exposure to BPA and bisphenol F (BPF) on assembled spindle stability in ovulated oocytes. Brief (4 h) exposure to increasing concentrations (5, 25, and 50 µg/mL) of BPA or BPF disrupted spindle organization in a dose-dependent manner, resulting in significantly shorter spindles with highly unfocused poles and fragmented pericentrin. The chromosomes remained congressed in an abnormally elongated metaphase-like configuration, yet normal end-on chromosome-MT attachments were reduced in BPF-treated oocytes. Live-cell imaging revealed a rapid onset of bisphenol-mediated spindle MT disruption that was reversed upon compound removal. Moreover, MT stability and regrowth were impaired in BPA-exposed oocytes, with few cold-stable MTs and formation of multipolar spindles upon MT regrowth. MT-associated kinesin-14 motor protein (HSET/KIFC1) labeling along the spindle was also lower in BPA-treated oocytes. Conversely, cold stable MTs and HSET labeling persisted after BPF exposure. Notably, inhibition of Aurora Kinase A limited bisphenol-mediated spindle pole widening, revealing a potential interaction. These results demonstrate rapid MT disrupting activity by bisphenols, which is highly detrimental to meiotic spindle stability and organization. Moreover, we identify an important link between these defects and altered distribution of key spindle associated factors as well as Aurora Kinase A activity.

scholarly journals Loss of aMTOCs disrupts spindle pole Aurora A and assembly of the liquid-like meiotic spindle domain (LISD) in oocytes

2021 ◽  
Author(s):  
Xiaotian Wang ◽  
Claudia Baumann ◽  
Rabindranath De La Fuente ◽  
Maria M. Viveiros
Keyword(s):  
Meiotic Division ◽  
Critical Role ◽  
Specific Inhibitor ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Aurora A ◽  
Microtubule Organizing Center ◽  
Spindle Poles ◽  
Organizing Center ◽  
Spindle Stability

Oocyte-specific Pericentrin (PCNT) knockdown in transgenic (Tg) mice disrupts acentriolar microtubule organizing center (aMTOC) formation, leading to spindle instability and error-prone meiotic division. Here, we show that PCNT-depleted oocytes lack phosphorylated Aurora A (pAURKA) at spindle poles, while overall levels are unaltered. To test aMTOC-associated AURKA function, MII control (WT) and Tg oocytes were briefly exposed to a specific inhibitor (MLN8237). Similar defects were observed in Tg and MLN8237-treated WT oocytes, including altered spindle structure, increased chromosome misalignment and impaired microtubule regrowth. Yet, AURKA inhibition had a limited effect on Tg oocytes, revealing a critical role for aMTOC-associated AURKA in regulating spindle stability. Notably, spindle instability was associated with disrupted γ-tubulin and lack of the liquid-like meiotic spindle domain (LISD) in Tg oocytes. Analysis of this Tg model provides the first evidence that LISD assembly depends expressly on aMTOC-associated AURKA, and that Ran-mediated spindle formation ensues without the LISD. These data support that loss of aMTOC-associated AURKA and failure of LISD assembly contribute to error-prone meiotic division in PCNT-depleted oocytes, underscoring the essential role of aMTOCs for spindle stability.

RAB35 depletion affects spindle formation and actin-based spindle migration in mouse oocyte meiosis

2019 ◽  
Vol 25 (7) ◽  
pp. 359-372 ◽  
Author(s):  
Yu Zhang ◽  
Xiang Wan ◽  
Hong-Hui Wang ◽  
Meng-Hao Pan ◽  
Zhen-Nan Pan ◽  
...  
Keyword(s):  
Asymmetric Cell Division ◽  
Polar Body ◽  
Asymmetric Division ◽  
Mouse Oocyte ◽  
Meiotic Spindle ◽  
Spindle Formation ◽  
Oocyte Meiosis ◽  
Spindle Stability ◽  
Polar Body Extrusion ◽  
Cytoskeleton Dynamics

Abstract Mammalian oocyte maturation involves a unique asymmetric cell division, in which meiotic spindle formation and actin filament-mediated spindle migration to the oocyte cortex are key processes. Here, we report that the vesicle trafficking regulator, RAB35 GTPase, is involved in regulating cytoskeleton dynamics in mouse oocytes. RAB35 GTPase mainly accumulated at the meiotic spindle periphery and cortex during oocyte meiosis. Depletion of RAB35 by morpholino microinjection led to aberrant polar body extrusion and asymmetric division defects in almost half the treated oocytes. We also found that RAB35 affected SIRT2 and αTAT for tubulin acetylation, which further modulated microtubule stability and meiotic spindle formation. Additionally, we found that RAB35 associated with RHOA in oocytes and modulated the ROCK–cofilin pathway for actin assembly, which further facilitated spindle migration for oocyte asymmetric division. Importantly, microinjection of Myc-Rab35 cRNA into RAB35-depleted oocytes could significantly rescue these defects. In summary, our results suggest that RAB35 GTPase has multiple roles in spindle stability and actin-mediated spindle migration in mouse oocyte meiosis.

scholarly journals WAVE2 regulates meiotic spindle stability, peripheral positioning and polar body emission in mouse oocytes

Cell Cycle ◽  
2011 ◽  
Vol 10 (11) ◽  
pp. 1853-1860 ◽  
Author(s):  
Shao-Chen Sun ◽  
Yong-Nan Xu ◽  
Ying-Hua Li ◽  
Seung-Eun Lee ◽  
Yong-Xun Jin ◽  
...  
Keyword(s):  
Polar Body ◽  
Meiotic Spindle ◽  
Mouse Oocytes ◽  
Spindle Stability
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