<i>Xenopus</i> oocyte meiosis lacks spindle assembly checkpoint control

Shao, Hua; Ma, Chunsheng; Chen, Eric; Li, Ruizhen

doi:10.1083/jcb.201211041

Cited by 46 publications

(47 citation statements)

References 45 publications

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“…It is possible that the decreased oocyte volume is responsible for the increased efficacy of the SAC. Evidence to support the relationship between SAC activity and nuclear volume comes from Xenopus oocytes, which are far larger in volume and completely lack a SAC response (Shao et al, 2013). In Xenopus cell-free extracts, a SAC response is also absent, but can be induced by increasing nuclear density through addition of sperm nuclei (Minshull et al, 1994).…”

Section: What Satisfies the Sac Surveillance Mechanism In Oocytes?mentioning

confidence: 99%

Molecular causes of aneuploidy in mammalian eggs

2013

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SummaryMammalian oocytes are particularly error prone in segregating their chromosomes during their two meiotic divisions. This results in the creation of an embryo that has inherited the wrong number of chromosomes: it is aneuploid. The incidence of aneuploidy rises significantly with maternal age and so there is much interest in understanding this association and the underlying causes of aneuploidy. The spindle assembly checkpoint, a surveillance mechanism that operates in all cells to prevent chromosome mis-segregation, and the cohesive ties that hold those chromosomes together, have thus both been the subject of intensive investigation in oocytes. It is possible that a lowered sensitivity of the spindle assembly checkpoint to certain types of chromosome attachment error may endow oocytes with an innate susceptibility to aneuploidy, which is made worse by an age-related loss in the factors that hold the chromosomes together.

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Section: What Satisfies the Sac Surveillance Mechanism In Oocytes?mentioning

confidence: 99%

Molecular causes of aneuploidy in mammalian eggs

2013

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“…The type of aneuploidy occurring is usually the loss of one chromosome at the first meiotic division. X. laevis oocytes undergo metaphase-to-anaphase transition of meiosis I in the presence of nocodazole, which destabilizes spindles and activates the spindle checkpoint in cells harboring a functional SAC (Shao et al 2013). In D. melanogaster oocytes, loss of checkpoint components does not affect Cyclin B degradation, as expected in the presence of a functional spindle checkpoint (Batiha and Swan 2012).…”

Section: Mouse Oocytes Have a Spindle Checkpoint Too!mentioning

confidence: 98%

How oocytes try to get it right: spindle checkpoint control in meiosis

Touati

Wassmann

2015

Chromosoma

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The generation of a viable, diploid organism depends on the formation of haploid gametes, oocytes, and spermatocytes, with the correct number of chromosomes. Halving the genome requires the execution of two consecutive specialized cell divisions named meiosis I and II. Unfortunately, and in contrast to male meiosis, chromosome segregation in oocytes is error prone, with human oocytes being extraordinarily "meiotically challenged". Aneuploid oocytes, that are with the wrong number of chromosomes, give rise to aneuploid embryos when fertilized. In humans, most aneuploidies are lethal and result in spontaneous abortions. However, some trisomies survive to birth or even adulthood, such as the well-known trisomy 21, which gives rise to Down syndrome (Nagaoka et al. in Nat Rev Genet 13:493-504, 2012). A staggering 20-25 % of oocytes ready to be fertilized are aneuploid in humans. If this were not bad enough, there is an additional increase in meiotic missegregations as women get closer to menopause. A woman above 40 has a risk of more than 30 % of getting pregnant with a trisomic child. Worse still, in industrialized western societies, child birth is delayed, with women getting their first child later in life than ever. This trend has led to an increase of trisomic pregnancies by 70 % in the last 30 years (Nagaoka et al. in Nat Rev Genet 13:493-504, 2012; Schmidt et al. in Hum Reprod Update 18:29-43, 2012). To understand why errors occur so frequently during the meiotic divisions in oocytes, we review here the molecular mechanisms at works to control chromosome segregation during meiosis. An important mitotic control mechanism, namely the spindle assembly checkpoint or SAC, has been adapted to the special requirements of the meiotic divisions, and this review will focus on our current knowledge of SAC control in mammalian oocytes. Knowledge on how chromosome segregation is controlled in mammalian oocytes may help to identify risk factors important for questions related to human reproductive health.

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“…Genetic evidence also argues against a role for the SAC in inhibiting APC/C activity in the 2nd meiotic division [54]. This apparent lack of a requirement for the SAC in female meiosis is also seen in Xenopus female meiosis [55].…”

Section: Inhibition Of Apc/c During Meiosis I Arrestmentioning

confidence: 98%

Cell Cycle Regulators in Female Meiosis of Drosophila melanogaster

Bourouh¹,

Swan²

2018

Drosophila Melanogaster - Model for Recent Advances in Genetics and Therapeutics

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Meiosis is a highly regulated and complex variation on the canonical cell cycle. It depends on the activity of most of the known mitotic cell cycle regulators, as well as many meiosis-specific factors that interact with and modify the activities of this core cell cycle machinery. This review will examine the roles of known mitotic cell cycle regulators and meiosis-specific factors in Drosophila female meiosis, focusing on three important meiotic events: nuclear envelope breakdown or maturation, establishment of the meiosis I spindle, and release from metaphase I arrest at ovulation. Many meiotic processes are controlled by the mitotic kinase, Cdk1 with its cyclin partners, cyclins A, B, and B3. Other major mitotic kinases, including Polo and Aurora B have been found to play multiple roles in Drosophila meiosis. The Anaphase Promoting Complex or Cyclosome (APC/C) controls many meiotic processes through regulation of Cdk1, the sister chromatid cohesion regulator, Separase and other targets. This review will focus on these and other meiotic regulators, emphasizing some of the technical advances that have driven the field forward in recent years, and highlighting gaps that need to be filled to achieve a more complete picture of how meiosis is regulated in Drosophila.

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Xenopus oocyte meiosis lacks spindle assembly checkpoint control

Abstract: In contrast to the situation in mammalian oocytes, the metaphase-to-anaphase transition in frog oocytes is not regulated by a spindle assembly checkpoint.

Cited by 46 publications

References 45 publications

Molecular causes of aneuploidy in mammalian eggs

Molecular causes of aneuploidy in mammalian eggs

How oocytes try to get it right: spindle checkpoint control in meiosis

Cell Cycle Regulators in Female Meiosis of Drosophila melanogaster

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