Loss of centromeric RNA activates the spindle assembly checkpoint in mammalian female meiosis I

2021 ◽  
Vol 220 (10) ◽  
Author(s):  
Tianyu Wu ◽  
Simon I.R. Lane ◽  
Stephanie L. Morgan ◽  
Feng Tang ◽  
Keith T. Jones

The repetitive sequences of DNA centromeric regions form the structural basis for kinetochore assembly. Recently they were found to be transcriptionally active in mitosis, with their RNAs providing noncoding functions. Here we explore the role, in mouse oocytes, of transcripts generated from within the minor satellite repeats. Depletion of minor satellite transcripts delayed progression through meiosis I by activation of the spindle assembly checkpoint. Arrested oocytes had poorly congressed chromosomes, and centromeres were frequently split by microtubules. Thus, we have demonstrated that the centromeric RNA plays a specific role in female meiosis I compared with mitosis and is required for maintaining the structural integrity of centromeres. This may contribute to the high aneuploidy rates observed in female meiosis.

2014 ◽  
Vol 204 (6) ◽  
pp. 891-900 ◽  
Author(s):  
Ibtissem Nabti ◽  
Petros Marangos ◽  
Jenny Bormann ◽  
Nobuaki R. Kudo ◽  
John Carroll

Female meiosis is driven by the activities of two major kinases, cyclin-dependent kinase 1 (Cdk1) and mitogen-activated protein kinase (MAPK). To date, the role of MAPK in control of meiosis is thought to be restricted to maintaining metaphase II arrest through stabilizing Cdk1 activity. In this paper, we find that MAPK and Cdk1 play compensatory roles to suppress the anaphase-promoting complex/cyclosome (APC/C) activity early in prometaphase, thereby allowing accumulation of APC/C substrates essential for meiosis I. Furthermore, inhibition of MAPK around the onset of APC/C activity at the transition from meiosis I to meiosis II led to accelerated completion of meiosis I and an increase in aneuploidy at metaphase II. These effects appear to be mediated via a Cdk1/MAPK-dependent stabilization of the spindle assembly checkpoint, which when inhibited leads to increased APC/C activity. These findings demonstrate new roles for MAPK in the regulation of meiosis in mammalian oocytes.


Cell Cycle ◽  
2005 ◽  
Vol 4 (5) ◽  
pp. 650-653 ◽  
Author(s):  
Hayden A. Homer ◽  
Alex McDougal ◽  
Mark Levasseur ◽  
Mary Herbert

Genome ◽  
2012 ◽  
Vol 55 (1) ◽  
pp. 63-67 ◽  
Author(s):  
Osamah Batiha ◽  
Andrew Swan

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.


2013 ◽  
Vol 23 (24) ◽  
pp. 2534-2539 ◽  
Author(s):  
Kikuë Tachibana-Konwalski ◽  
Jonathan Godwin ◽  
Máté Borsos ◽  
Ahmed Rattani ◽  
David J. Adams ◽  
...  

Reproduction ◽  
2016 ◽  
Vol 152 (1) ◽  
pp. R15-R22 ◽  
Author(s):  
Josie K Collins ◽  
Keith T Jones

DNA damage acquired during meiosis can lead to infertility and miscarriage. Hence, it should be important for an oocyte to be able to detect and respond to such events in order to make a healthy egg. Here, the strategies taken by oocytes during their stages of growth to respond to DNA damaging events are reviewed. In particular, recent evidence of a novel pathway in fully grown oocytes helps prevent the formation of mature eggs with DNA damage. It has been found that fully grown germinal vesicle stage oocytes that have been DNA damaged do not arrest at this point in meiosis, but instead undergo meiotic resumption and stall during the first meiotic division. The Spindle Assembly Checkpoint, which is a well-known mitotic pathway employed by somatic cells to monitor chromosome attachment to spindle microtubules, appears to be utilised by oocytes also to respond to DNA damage. As such maturing oocytes are arrested at metaphase I due to an active Spindle Assembly Checkpoint. This is surprising given this checkpoint has been previously studied in oocytes and considered to be weak and ineffectual because of its poor ability to be activated in response to microtubule attachment errors. Therefore, the involvement of the Spindle Assembly Checkpoint in DNA damage responses of mature oocytes during meiosis I uncovers a novel second function for this ubiquitous cellular checkpoint.


2017 ◽  
Vol 216 (12) ◽  
pp. 3949-3957 ◽  
Author(s):  
Simon I.R. Lane ◽  
Keith T. Jones

The spindle assembly checkpoint (SAC) prevents chromosome missegregation by coupling anaphase onset with correct chromosome attachment and tension to microtubules. It does this by generating a diffusible signal from free kinetochores into the cytoplasm, inhibiting the anaphase-promoting complex (APC). The volume in which this signal remains effective is unknown. This raises the possibility that cell volume may be the reason the SAC is weak, and chromosome segregation error-prone, in mammalian oocytes. Here, by a process of serial bisection, we analyzed the influence of oocyte volume on the ability of the SAC to inhibit bivalent segregation in meiosis I. We were able to generate oocytes with cytoplasmic volumes reduced by 86% and observed changes in APC activity consistent with increased SAC control. However, bivalent biorientation remained uncoupled from APC activity, leading to error-prone chromosome segregation. We conclude that volume is one factor contributing to SAC weakness in oocytes. However, additional factors likely uncouple chromosome biorientation with APC activity.


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