scholarly journals CDC6 regulates both G2/M transition and metaphase-to-anaphase transition during the first meiosis of mouse oocytes

2019 ◽  
Author(s):  
Zi-Yun Yi ◽  
Tie-Gang Meng ◽  
Xue-Shan Ma ◽  
Jian Li ◽  
Chun-Hui Zhang ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Time Lapse ◽  
Cyclin B1 ◽  
Meiotic Spindle ◽  
G2 Arrest ◽  
Mouse Oocytes ◽  
Summary Statement ◽  
Initiation Of Dna Replication ◽  
Oocyte Meiotic Maturation

AbstractCell division cycle protein CDC6 is essential for the initiation of DNA replication. CDC6 was recently shown to inhibit the microtubule-organizing activity of the centrosome. Here, we show that CDC6 is localized to the spindle from Pro-MI to MII stages of oocytes, and it plays important roles at two critical steps of oocyte meiotic maturation. CDC6 depletion facilitated the G2/M transition (GV breakdown, GVBD) through regulation of Cdh1 and cyclin B1 expression and CDK1 phosphorylation in a GVBD-inhibiting culture system containing milrinone. Furthermore, GVBD was significantly decreased after knockdown of cyclin B1 in CDC6-depleted oocytes, indicating that the effect of CDC6 loss on GVBD stimulation was mediated, at least in part, by raising cyclin B1. Knockdown of CDC6 also caused abnormal localization of γ-tubulin, resulting in defective spindles, misaligned chromosomes, cyclin B1 accumulation and spindle assembly checkpoint (SAC) activation, leading to significant Pro-MI/MI arrest and PB1 extrusion failure. These phenotypes were also confirmed by time-lapse live cell imaging analysis. The results indicate that CDC6 is indispensable for maintaining G2 arrest of meiosis and functions in G2/M checkpoint regulation in mouse oocytes. Moreover, CDC6 is also a key player regulating meiotic spindle assembly and metaphase-to-anaphase transition in meiotic oocytes.Summary statementWe show that CDC6 is indispensable for maintaining G2 arrest of mouse oocytes. Moreover, CDC6 is also a key player regulating meiotic spindle assembly and metaphase-to-anaphase transition in meiotic oocytes.

scholarly journals APCFZR1 prevents nondisjunction in mouse oocytes by controlling meiotic spindle assembly timing

2012 ◽  
Vol 23 (20) ◽  
pp. 3970-3981 ◽  
Author(s):  
Janet E. Holt ◽  
Simon I. R. Lane ◽  
Phoebe Jennings ◽  
Irene García-Higuera ◽  
Sergio Moreno ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Mitotic Cell ◽  
Meiotic Spindle ◽  
Genome Integrity ◽  
Mitotic Cell Cycle ◽  
Anaphase Promoting Complex ◽  
Mouse Oocytes ◽  
M Phase ◽  
Chromosome Nondisjunction

FZR1 is an anaphase-promoting complex (APC) activator best known for its role in the mitotic cell cycle at M-phase exit, in G1, and in maintaining genome integrity. Previous studies also established that it prevents meiotic resumption, equivalent to the G2/M transition. Here we report that mouse oocytes lacking FZR1 undergo passage through meiosis I that is accelerated by ∼1 h, and this is due to an earlier onset of spindle assembly checkpoint (SAC) satisfaction and APCCDC20 activity. However, loss of FZR1 did not compromise SAC functionality; instead, earlier SAC satisfaction was achieved because the bipolar meiotic spindle was assembled more quickly in the absence of FZR1. This novel regulation of spindle assembly by FZR1 led to premature bivalent attachment to microtubules and loss of kinetochore-bound MAD2. Bivalents, however, were observed to congress poorly, leading to nondisjunction rates of 25%. We conclude that in mouse oocytes FZR1 controls the timing of assembly of the bipolar spindle and in so doing the timing of SAC satisfaction and APCCDC20 activity. This study implicates FZR1 as a major regulator of prometaphase whose activity helps to prevent chromosome nondisjunction.

scholarly journals The spindle assembly checkpoint is not essential for CSF arrest of mouse oocytes

2004 ◽  
Vol 167 (6) ◽  
pp. 1037-1050 ◽  
Author(s):  
Chizuko Tsurumi ◽  
Steffen Hoffmann ◽  
Stephan Geley ◽  
Ralph Graeser ◽  
Zbigniew Polanski
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Dominant Negative ◽  
Meiotic Spindle ◽  
Anaphase Promoting Complex ◽  
Mouse Oocytes ◽  
Cytostatic Factor ◽  
C Complex ◽  
Meiosis I

In Xenopus oocytes, the spindle assembly checkpoint (SAC) kinase Bub1 is required for cytostatic factor (CSF)-induced metaphase arrest in meiosis II. To investigate whether matured mouse oocytes are kept in metaphase by a SAC-mediated inhibition of the anaphase-promoting complex/cyclosome (APC/C) complex, we injected a dominant-negative Bub1 mutant (Bub1dn) into mouse oocytes undergoing meiosis in vitro. Passage through meiosis I was accelerated, but even though the SAC was disrupted, injected oocytes still arrested at metaphase II. Bub1dn-injected oocytes released from CSF and treated with nocodazole to disrupt the second meiotic spindle proceeded into interphase, whereas noninjected control oocytes remained arrested at metaphase. Similar results were obtained using dominant-negative forms of Mad2 and BubR1, as well as checkpoint resistant dominant APC/C activating forms of Cdc20. Thus, SAC proteins are required for checkpoint functions in meiosis I and II, but, in contrast to frog eggs, the SAC is not required for establishing or maintaining the CSF arrest in mouse oocytes.

scholarly journals The Aurora kinase inhibitor ZM447439 accelerates first meiosis in mouse oocytes by overriding the spindle assembly checkpoint

Reproduction ◽  
2010 ◽  
Vol 140 (4) ◽  
pp. 521-530 ◽  
Author(s):  
Simon I R Lane ◽  
Heng-Yu Chang ◽  
Phoebe C Jennings ◽  
Keith T Jones
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Kinase Inhibitor ◽  
Polar Body ◽  
Spindle Assembly ◽  
Aurora Kinase ◽  
Mitotic Cell ◽  
Cyclin B1 ◽  
Anaphase Promoting Complex ◽  
Mouse Oocytes ◽  
Polar Body Extrusion

Previous studies have established that when maturing mouse oocytes are continuously incubated with the Aurora inhibitor ZM447439, meiotic maturation is blocked. In this study, we observe that by altering the time of addition of the inhibitor, oocyte maturation can actually be accelerated by 1 h as measured by the timing of polar body extrusion. ZM447439 also had the ability to overcome a spindle assembly checkpoint (SAC) arrest caused by nocodazole and so rescue polar body extrusion. Consistent with the ability of the SAC to inhibit cyclin B1 degradation by blocking activation of the anaphase-promoting complex, we could also observe a rescue in cyclin B1 degradation when ZM447439 was added to nocodazole-treated oocytes. The acceleration of the first meiotic division by ZM447439, which has not been achieved previously, and its effects on the SAC are all consistent with the proposed mitotic role of Aurora B in activating the SAC. We hypothesize that Aurora kinase activity controls the SAC in meiosis I, despite differences to the mitotic cell cycle division in spindle architecture brought about by the meiotic mono-orientation of sister kinetochores.

scholarly journals Antagonizing the spindle assembly checkpoint silencing enhances paclitaxel and Navitoclax-mediated apoptosis with distinct mechanistic

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana C. Henriques ◽  
Patrícia M. A. Silva ◽  
Bruno Sarmento ◽  
Hassan Bousbaa
Keyword(s):  
Cell Death ◽  
Cancer Cells ◽  
Cell Fate ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Time Lapse ◽  
Antimitotic Drugs ◽  
Mitotic Slippage ◽  
Mitotic Death ◽  
Chronic Activation

AbstractAntimitotic drugs arrest cells in mitosis through chronic activation of the spindle assembly checkpoint (SAC), leading to cell death. However, drug-treated cancer cells can escape death by undergoing mitotic slippage, due to premature mitotic exit. Therefore, overcoming slippage issue is a promising chemotherapeutic strategy to improve the effectiveness of antimitotics. Here, we antagonized SAC silencing by knocking down the MAD2-binding protein p31comet, to delay mitotic slippage, and tracked cancer cells treated with the antimitotic drug paclitaxel, over 3 days live-cell time-lapse analysis. We found that in the absence of p31comet, the duration of mitotic block was increased in cells challenged with nanomolar concentrations of paclitaxel, leading to an additive effects in terms of cell death which was predominantly anticipated during the first mitosis. As accumulation of an apoptotic signal was suggested to prevent mitotic slippage, when we challenged p31comet-depleted mitotic-arrested cells with the apoptosis potentiator Navitoclax (previously called ABT-263), cell fate was shifted to accelerated post-mitotic death. We conclude that inhibition of SAC silencing is critical for enhancing the lethality of antimitotic drugs as well as that of therapeutic apoptosis-inducing small molecules, with distinct mechanisms. The study highlights the potential of p31comet as a target for antimitotic therapies.

scholarly journals DNA damage induces a meiotic arrest in mouse oocytes mediated by the spindle assembly checkpoint

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Josie K. Collins ◽  
Simon I. R. Lane ◽  
Julie A. Merriman ◽  
Keith T. Jones
Keyword(s):  
Dna Damage ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Meiotic Arrest ◽  
Mouse Oocytes

scholarly journals Orchestration of the spindle assembly checkpoint by CDK1‐cyclin B1

FEBS Letters ◽  
2019 ◽  
Vol 593 (20) ◽  
pp. 2889-2907 ◽  
Author(s):  
Daniel Hayward ◽  
Tatiana Alfonso‐Pérez ◽  
Ulrike Gruneberg
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Cyclin B1

Evidence that the spindle assembly checkpoint does not regulate APCFzy activity in Drosophila female meiosis

Genome ◽  
2012 ◽  
Vol 55 (1) ◽  
pp. 63-67 ◽  
Author(s):  
Osamah Batiha ◽  
Andrew Swan
Keyword(s):  
Chromosome Segregation ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Cyclin B ◽  
Meiotic Spindle ◽  
Loss Of Function ◽  
Female Meiosis ◽  
Chromosome Attachment ◽  
Spindle Microtubules ◽  
Made In

The spindle assembly checkpoint (SAC) plays an important role in mitotic cells to sense improper chromosome attachment to spindle microtubules and to inhibit APCFzy-dependent destruction of cyclin B and Securin; consequent initiation of anaphase until correct attachments are made. In Drosophila , SAC genes have been found to play a role in ensuring proper chromosome segregation in meiosis, possibly reflecting a similar role for the SAC in APCFzy inhibition during meiosis. We found that loss of function mutations in SAC genes, Mad2, zwilch, and mps1, do not lead to the predicted rise in APCFzy-dependent degradation of cyclin B either globally throughout the egg or locally on the meiotic spindle. Further, the SAC is not responsible for the inability of APCFzy to target cyclin B and promote anaphase in metaphase II arrested eggs from cort mutant females. Our findings support the argument that SAC proteins play checkpoint independent roles in Drosophila female meiosis and that other mechanisms must function to control APC activity.

scholarly journals Anastral meiotic spindle morphogenesis: role of the non-claret disjunctional kinesin-like protein.

1996 ◽  
Vol 134 (2) ◽  
pp. 455-464 ◽  
Author(s):  
H J Matthies ◽  
H B McDonald ◽  
L S Goldstein ◽  
W E Theurkauf
Keyword(s):  
Laser Scanning ◽  
Spindle Assembly ◽  
Time Lapse ◽  
Laser Scanning Confocal Microscopy ◽  
Meiotic Spindle ◽  
Bipolar Spindle ◽  
Scanning Confocal Microscopy ◽  
Spindle Poles ◽  
Assembly Kinetics

We have used time-lapse laser scanning confocal microscopy to directly examine microtubule reorganization during meiotic spindle assembly in living Drosophila oocytes. These studies indicate that the bipolarity of the meiosis I spindle is not the result of a duplication and separation of centrosomal microtubule organizing centers (MTOCs). Instead, microtubules first associate with a tight chromatin mass, and then bundle to form a bipolar spindle that lacks asters. Analysis of mutant oocytes indicates that the Non-Claret Disjunctional (NCD) kinesin-like protein is required for normal spindle assembly kinetics and stabilization of the spindle during metaphase arrest. Immunolocalization analyses demonstrate that NCD is associated with spindle microtubules, and that the centrosomal components gamma-tubulin, CP-190, and CP-60 are not concentrated at the meiotic spindle poles. Based on these observations, we propose that microtubule bundling by the NCD kinesin-like protein promotes assembly of a stable bipolar spindle in the absence of typical MTOCs.

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