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Jung GI, Londoño-Vásquez D, Park S, Skop AR, Balboula AZ, Schindler K. An oocyte meiotic midbody cap is required for developmental competence in mice. Nat Commun 2023; 14:7419. [PMID: 37973997 PMCID: PMC10654508 DOI: 10.1038/s41467-023-43288-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023] Open
Abstract
Embryo development depends upon maternally derived materials. Mammalian oocytes undergo extreme asymmetric cytokinesis events, producing one large egg and two small polar bodies. During cytokinesis in somatic cells, the midbody and subsequent assembly of the midbody remnant, a signaling organelle containing RNAs, transcription factors and translation machinery, is thought to influence cellular function or fate. The role of the midbody and midbody remnant in gametes, in particular, oocytes, remains unclear. Here, we examined the formation and function of meiotic midbodies (mMB) and mMB remnants using mouse oocytes and demonstrate that mMBs have a specialized cap structure that is orientated toward polar bodies. We show that that mMBs are translationally active, and that mMB caps are required to retain nascent proteins in eggs. We propose that this specialized mMB cap maintains genetic factors in eggs allowing for full developmental competency.
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Affiliation(s)
- Gyu Ik Jung
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Human Genetics Institute of New Jersey, Piscataway, NJ, USA
| | | | - Sungjin Park
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Ahna R Skop
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Ahmed Z Balboula
- Animal Sciences Research Center, University of Missouri, Columbia, MO, USA
| | - Karen Schindler
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.
- Human Genetics Institute of New Jersey, Piscataway, NJ, USA.
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2
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Schindler K, Jung GI, Londoño-Vásquez D, Park S, Skop A, Balboula A. An oocyte meiotic midbody cap is required for developmental competence in mice. RESEARCH SQUARE 2023:rs.3.rs-3399188. [PMID: 37886573 PMCID: PMC10602078 DOI: 10.21203/rs.3.rs-3399188/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Embryo development depends upon maternally derived materials. Mammalian oocytes undergo extreme asymmetric cytokinesis events, producing one large egg and two small polar bodies (PB). During cytokinesis in somatic cells, the midbody (MB) and subsequent assembly of the midbody remnant (MBR), a signaling organelle containing RNAs, transcription factors and translation machinery, is thought to influence cellular function or fate. The role of the MB and MBR in gametes, in particular, oocytes, remains unclear. Here, we examined the formation and function of meiotic MBs (mMB) and mMB remnants (mMBRs) using mouse oocytes and demonstrate that mMBs have a specialized meiotic mMB cap structure that is orientated toward PBs. We show that that mMBs are translationally active, and that mMB caps are required to retain nascent proteins in eggs. We propose that this specialized mMB cap maintains genetic factors in eggs allowing for full developmental competency.
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3
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Crozet F, Letort G, Bulteau R, Da Silva C, Eichmuller A, Tortorelli AF, Blévinal J, Belle M, Dumont J, Piolot T, Dauphin A, Coulpier F, Chédotal A, Maître JL, Verlhac MH, Clarke HJ, Terret ME. Filopodia-like protrusions of adjacent somatic cells shape the developmental potential of oocytes. Life Sci Alliance 2023; 6:e202301963. [PMID: 36944420 PMCID: PMC10029974 DOI: 10.26508/lsa.202301963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/07/2023] [Accepted: 03/07/2023] [Indexed: 03/23/2023] Open
Abstract
The oocyte must grow and mature before fertilization, thanks to a close dialogue with the somatic cells that surround it. Part of this communication is through filopodia-like protrusions, called transzonal projections (TZPs), sent by the somatic cells to the oocyte membrane. To investigate the contribution of TZPs to oocyte quality, we impaired their structure by generating a full knockout mouse of the TZP structural component myosin-X (MYO10). Using spinning disk and super-resolution microscopy combined with a machine-learning approach to phenotype oocyte morphology, we show that the lack of Myo10 decreases TZP density during oocyte growth. Reduction in TZPs does not prevent oocyte growth but impairs oocyte-matrix integrity. Importantly, we reveal by transcriptomic analysis that gene expression is altered in TZP-deprived oocytes and that oocyte maturation and subsequent early embryonic development are partially affected, effectively reducing mouse fertility. We propose that TZPs play a role in the structural integrity of the germline-somatic complex, which is essential for regulating gene expression in the oocyte and thus its developmental potential.
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Affiliation(s)
- Flora Crozet
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Paris, France
- Department of Developmental and Stem Cell Biology, Institut Pasteur, CNRS UMR 3738, Université Paris Cité, Paris, France
| | - Gaëlle Letort
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Paris, France
- Department of Developmental and Stem Cell Biology, Institut Pasteur, CNRS UMR 3738, Université Paris Cité, Paris, France
| | - Rose Bulteau
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Christelle Da Silva
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Adrien Eichmuller
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Paris, France
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR 3215, INSERM U934, Paris, France
| | - Anna Francesca Tortorelli
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR 3215, INSERM U934, Paris, France
| | | | - Morgane Belle
- Institut de la Vision, UMRS968/UMR7210/UM80, Paris, France
| | - Julien Dumont
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Tristan Piolot
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Aurélien Dauphin
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR 3215, INSERM U934, Paris, France
| | - Fanny Coulpier
- Genomics Core Facility, Institut de Biologie de l'ENS, Département de biologie, Ecole normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Alain Chédotal
- Institut de la Vision, UMRS968/UMR7210/UM80, Paris, France
| | - Jean-Léon Maître
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR 3215, INSERM U934, Paris, France
| | - Marie-Hélène Verlhac
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Hugh J Clarke
- Department of Obstetrics and Gynecology, McGill University, Montreal, Canada
| | - Marie-Emilie Terret
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Paris, France
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4
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Tao R, Bi J, Zhu F, Wang X, Jia C, Xu H, He X, Li J. Division Behaviors and Their Effects on Preimplantation Development of Pig Embryos. Reprod Domest Anim 2022; 57:1016-1028. [PMID: 35662274 DOI: 10.1111/rda.14168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/10/2022] [Accepted: 05/28/2022] [Indexed: 11/27/2022]
Abstract
Quality of preimplantation embryos could affect development efficiency after embryo transfer. However, assessment of preimplantation embryos was unsatisfied especially in pig embryos to date. Therefore, the present study was design to investigate available and applicable parameters which indicating development potential and quality of porcine preimplantation embryos produced by handmade cloning (HMC), parthenogenetic activation without zona pellucida (PAZF) and with zona pellucida (PAZI). Results firstly detected a common division behavior that formation of uneven division with two unequal size blastomeres (UD 2-cell), especially in HMC embryos, the proportion of UD 2-cell was significantly higher than that of equal size blastomeres (ED 2-cell) with 72.56 ± 4.56 vs. 24.57 ± 1.92. Formation of UD 2-cell might due to spindle migrates along the long axis in 1-cell stage, and the cleavage furrow not formed in the center of cytoplasm. In the two sister blastomeres of UD 2-cell, unevenly distribution of organelles (mitochondria and lipid droplet) was observed with lower proportion in the smaller one (p<0.05). Althoug no difference of blastocyst rate was observed between UD and ED 2-cell embryos, the cell number per blastocyst from UD 2-cell embryos was lower than that from ED 2-cell embryos (44.15 ± 2.05 vs. 51.55 ± 1.83). Besides, because of nonsynchronized division of each blastomeres, another common behavior that three cleavage routes were observed in all of HMC/PAZF/PAZI embryos that T1 (2-cell → 3-cell → 4-cell → ≥ 5-cell → morula → blastocyst), T2 (2-cell → 3-cell → 4-cell → morula → blastocyst), and T3 (2-cell → 3-cell / 4-cell → morula → blastocyst). Therefore, in pig in vitro produced embryos, division behaviors of uneven volume of cytoplasm and nonsynchronized cell cycles were observed at the early embryonic developmental stage, which might be another potential factor to evaluate embryonic development.
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Affiliation(s)
- Ruixin Tao
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Jiaying Bi
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Fuquan Zhu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Xuguang Wang
- College of Animal Science and Technology, Xinjiang Agricultural University, Urimuqi, China
| | - Chao Jia
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Hongxia Xu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Xu He
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Juan Li
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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Blengini CS, Schindler K. Acentriolar spindle assembly in mammalian female meiosis and the consequences of its perturbations on human reproduction. Biol Reprod 2021; 106:253-263. [PMID: 34791041 DOI: 10.1093/biolre/ioab210] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/26/2021] [Accepted: 11/11/2021] [Indexed: 12/18/2022] Open
Abstract
The purpose of meiosis is to generate developmentally competent, haploid gametes with the correct number of chromosomes. For reasons not completely understood, female meiosis is more prone to chromosome segregation errors than meiosis in males, leading to an abnormal number of chromosomes, or aneuploidy, in gametes. Meiotic spindles are the cellular machinery essential for the proper segregation of chromosomes. One unique feature of spindle structures in female meiosis is spindles poles that lack centrioles. The process of building a meiotic spindle without centrioles is complex and requires precise coordination of different structural components, assembly factors, motor proteins, and signaling molecules at specific times and locations to regulate each step. In this review, we discuss the basics of spindle formation during oocyte meiotic maturation focusing on mouse and human studies. Finally, we review different factors that could alter the process of spindle formation and its stability. We conclude with a discussion of how different assisted reproductive technologies (ART) could affect spindles and the consequences these perturbations may have for subsequent embryo development.
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Affiliation(s)
- Cecilia S Blengini
- Rutgers University, Human Genetics Institute of New Jersey, Piscataway, NJ 08854 USA
| | - Karen Schindler
- Rutgers University, Human Genetics Institute of New Jersey, Piscataway, NJ 08854 USA
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Hu LL, Pan MH, Yang FL, Zong ZA, Tang F, Pan ZN, Lu X, Ren YP, Wang JL, Sun SC. FASCIN regulates actin assembly for spindle movement and polar body extrusion in mouse oocyte meiosis. J Cell Physiol 2021; 236:7725-7733. [PMID: 34018605 DOI: 10.1002/jcp.30443] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 04/07/2021] [Accepted: 05/12/2021] [Indexed: 01/15/2023]
Abstract
During mouse oocyte meiotic maturation, actin filaments play multiple roles in meiosis such as spindle migration and cytokinesis. FASCIN is shown to be an actin-binding and bundling protein, making actin filaments tightly packed and parallel-aligned, and FASCIN is involved in several cellular processes like adhesion and migration. FASCIN is also a potential prognostic biomarker and therapeutic target for the treatment of metastatic disease. However, little is known about the functions of FASCIN in oocyte meiosis. In the present study, we knocked down the expression of FASCIN, and our results showed that FASCIN was essential for oocyte maturation. FASCIN was all expressed in the different stages of oocyte meiosis, and it mainly localized at the cortex of oocytes from the GV stage to the MII stage and showed a similar localization pattern with actin and DAAM1. Depletion of FASCIN affected the extrusion of the first polar body, and we also observed that some oocytes extruded from the large polar bodies. This might have resulted from the defects of actin assembly, which further affected the meiotic spindle positioning. In addition, we showed that inhibition of PKC activity decreased FASCIN expression, indicating that FASCIN might be regulated by PKC. Taken together, our results provided evidence for the important role of FASCIN on actin filaments for spindle migration and polar body extrusion in mouse oocyte meiosis.
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Affiliation(s)
- Lin-Lin Hu
- Reproductive Medicine Center, the Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
- School of Laboratory Medicine, Youjiang Medical University for Nationalities, Baise, China
| | - Meng-Hao Pan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Feng-Lian Yang
- School of Laboratory Medicine, Youjiang Medical University for Nationalities, Baise, China
| | - Zi-Ao Zong
- School of Laboratory Medicine, Youjiang Medical University for Nationalities, Baise, China
| | - Feng Tang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Zhen-Nan Pan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Xiang Lu
- College of Basic Medical Sciences, Zunyi Medical University, Zunyi, China
| | - Yan-Ping Ren
- College of Basic Medical Sciences, Zunyi Medical University, Zunyi, China
| | - Jun-Li Wang
- School of Laboratory Medicine, Youjiang Medical University for Nationalities, Baise, China
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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7
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Dehapiot B, Clément R, Bourdais A, Carrière V, Huet S, Halet G. RhoA- and Cdc42-induced antagonistic forces underlie symmetry breaking and spindle rotation in mouse oocytes. PLoS Biol 2021; 19:e3001376. [PMID: 34491981 PMCID: PMC8448345 DOI: 10.1371/journal.pbio.3001376] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 09/17/2021] [Accepted: 07/30/2021] [Indexed: 11/25/2022] Open
Abstract
Mammalian oocyte meiotic divisions are highly asymmetric and produce a large haploid gamete and 2 small polar bodies. This relies on the ability of the cell to break symmetry and position its spindle close to the cortex before anaphase occurs. In metaphase II–arrested mouse oocytes, the spindle is actively maintained close and parallel to the cortex, until fertilization triggers sister chromatid segregation and the rotation of the spindle. The latter must indeed reorient perpendicular to the cortex to enable cytokinesis ring closure at the base of the polar body. However, the mechanisms underlying symmetry breaking and spindle rotation have remained elusive. In this study, we show that spindle rotation results from 2 antagonistic forces. First, an inward contraction of the cytokinesis furrow dependent on RhoA signaling, and second, an outward attraction exerted on both sets of chromatids by a Ran/Cdc42-dependent polarization of the actomyosin cortex. By combining live segmentation and tracking with numerical modeling, we demonstrate that this configuration becomes unstable as the ingression progresses. This leads to spontaneous symmetry breaking, which implies that neither the rotation direction nor the set of chromatids that eventually gets discarded are biologically predetermined. Mammalian oocyte meiotic divisions are highly asymmetric and produce a large haploid gamete and two small polar bodies, but the mechanisms underlying the required symmetry breaking and spindle rotation have remained elusive. This study shows that spindle rotation in activated mouse oocytes relies on spontaneous symmetry breaking resulting from an unstable configuration generated by cleavage furrow ingression and cortical chromosome attraction.
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Affiliation(s)
- Benoit Dehapiot
- Aix Marseille Université, CNRS, IBDM-UMR7288, Turing Center for Living Systems, Marseille, France
- Univ Rennes, CNRS, IGDR—UMR 6290, Rennes, France
- * E-mail: (BD); (GH)
| | - Raphaël Clément
- Aix Marseille Université, CNRS, IBDM-UMR7288, Turing Center for Living Systems, Marseille, France
| | | | | | | | - Guillaume Halet
- Univ Rennes, CNRS, IGDR—UMR 6290, Rennes, France
- * E-mail: (BD); (GH)
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Greaney J, Subramanian GN, Ye Y, Homer H. Isolation and in vitro Culture of Mouse Oocytes. Bio Protoc 2021; 11:e4104. [PMID: 34458398 DOI: 10.21769/bioprotoc.4104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/11/2021] [Accepted: 04/12/2021] [Indexed: 11/02/2022] Open
Abstract
Females are endowed at birth with a fixed reserve of oocytes, which declines both in quantity and quality with advancing age. Understanding the molecular mechanisms regulating oocyte quality is crucial for improving the chances of pregnancy success in fertility clinics. In vitro culture systems enable researchers to analyse important molecular and genetic regulators of oocyte maturation and fertilisation. Here, we describe in detail a highly reproducible technique for the isolation and culture of fully grown mouse oocytes. We include the considerations and precautionary measures required for minimising the detrimental effects of in vitro culture conditions. This technique forms the starting point for a wide range of experimental approaches such as post-transcriptional gene silencing, immunocytochemistry, Western blotting, high-resolution 4D time-lapse imaging, and in vitro fertilization, which are instrumental in dissecting the molecular determinants of oocyte quality. Hence, this protocol serves as a useful, practical guide for any oocyte researcher beginning experiments aimed at investigating important oocyte molecular factors. Graphic abstract: A step-by-step protocol for the isolation and in vitro culture of oocytes from mice.
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Affiliation(s)
- Jessica Greaney
- The Christopher Chen Oocyte Biology Research Laboratory, University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia
| | - Goutham Narayanan Subramanian
- The Christopher Chen Oocyte Biology Research Laboratory, University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia
| | - Yunan Ye
- The Christopher Chen Oocyte Biology Research Laboratory, University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia
| | - Hayden Homer
- The Christopher Chen Oocyte Biology Research Laboratory, University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Australia
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9
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Scheffler K, Uraji J, Jentoft I, Cavazza T, Mönnich E, Mogessie B, Schuh M. Two mechanisms drive pronuclear migration in mouse zygotes. Nat Commun 2021; 12:841. [PMID: 33547291 PMCID: PMC7864974 DOI: 10.1038/s41467-021-21020-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 12/28/2020] [Indexed: 12/13/2022] Open
Abstract
A new life begins with the unification of the maternal and paternal chromosomes upon fertilization. The parental chromosomes first become enclosed in two separate pronuclei near the surface of the fertilized egg. The mechanisms that then move the pronuclei inwards for their unification are only poorly understood in mammals. Here, we report two mechanisms that act in concert to unite the parental genomes in fertilized mouse eggs. The male pronucleus assembles within the fertilization cone and is rapidly moved inwards by the flattening cone. Rab11a recruits the actin nucleation factors Spire and Formin-2 into the fertilization cone, where they locally nucleate actin and further accelerate the pronucleus inwards. In parallel, a dynamic network of microtubules assembles that slowly moves the male and female pronuclei towards the cell centre in a dynein-dependent manner. Both mechanisms are partially redundant and act in concert to unite the parental pronuclei in the zygote's centre.
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Affiliation(s)
- Kathleen Scheffler
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- School of Biochemistry, University of Bristol, Bristol, UK
| | - Julia Uraji
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ida Jentoft
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Tommaso Cavazza
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Eike Mönnich
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | | | - Melina Schuh
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
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10
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Abstract
Chromosome segregation errors in human oocytes lead to aneuploid embryos that cause infertility and birth defects. Here we provide an overview of the chromosome-segregation process in the mammalian oocyte, highlighting mechanistic differences between oocytes and somatic cells that render oocytes so prone to segregation error. These differences include the extremely large size of the oocyte cytoplasm, the unique geometry of meiosis-I chromosomes, idiosyncratic function of the spindle assembly checkpoint, and dramatically altered oocyte cell-cycle control and spindle assembly, as compared to typical somatic cells. We summarise recent work suggesting that aging leads to a further deterioration in fidelity of chromosome segregation by impacting multiple components of the chromosome-segregation machinery. In addition, we compare and contrast recent results from mouse and human oocytes, which exhibit overlapping defects to differing extents. We conclude that the striking propensity of the oocyte to mis-segregate chromosomes reflects the unique challenges faced by the spindle in a highly unusual cellular environment.
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Affiliation(s)
- Aleksandar I Mihajlović
- Centre Recherche CHUM and Department OBGYN, Université de Montreal, Montreal, Quebec, Canada
| | - Greg FitzHarris
- Centre Recherche CHUM and Department OBGYN, Université de Montreal, Montreal, Quebec, Canada.
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11
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He YT, Wang W, Shen W, Sun QY, Yin S. Melatonin protects against Fenoxaprop-ethyl exposure-induced meiotic defects in mouse oocytes. Toxicology 2019; 425:152241. [DOI: 10.1016/j.tox.2019.152241] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/11/2019] [Accepted: 06/28/2019] [Indexed: 12/14/2022]
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12
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Uraji J, Scheffler K, Schuh M. Functions of actin in mouse oocytes at a glance. J Cell Sci 2018; 131:131/22/jcs218099. [PMID: 30467138 DOI: 10.1242/jcs.218099] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Gametes undergo a specialized and reductional cell division termed meiosis. Female gametes (oocytes) undergo two rounds of meiosis; the first meiotic division produces the fertilizable egg, while the second meiotic division occurs upon fertilization. Both meiotic divisions are highly asymmetric, producing a large egg and small polar bodies. Actin takes over various essential function during oocyte meiosis, many of which commonly rely on microtubules in mitotic cells. Specifically, the actin network has been linked to long-range vesicle transport, nuclear positioning, spindle migration and anchorage, polar body extrusion and accurate chromosome segregation in mammalian oocytes. In this Cell Science at a Glance article and the accompanying poster, we summarize the many functions of the actin cytoskeleton in oocytes, with a focus on findings from the mouse model system.
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Affiliation(s)
- Julia Uraji
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Kathleen Scheffler
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Melina Schuh
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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13
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Animal Female Meiosis: The Challenges of Eliminating Centrosomes. Cells 2018; 7:cells7070073. [PMID: 29996518 PMCID: PMC6071224 DOI: 10.3390/cells7070073] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/03/2018] [Accepted: 07/03/2018] [Indexed: 01/02/2023] Open
Abstract
Sexual reproduction requires the generation of gametes, which are highly specialised for fertilisation. Female reproductive cells, oocytes, grow up to large sizes when they accumulate energy stocks and store proteins as well as mRNAs to enable rapid cell divisions after fertilisation. At the same time, metazoan oocytes eliminate their centrosomes, i.e., major microtubule-organizing centres (MTOCs), during or right after the long growth phases. Centrosome elimination poses two key questions: first, how can the centrosome be re-established after fertilisation? In general, metazoan oocytes exploit sperm components, i.e., the basal body of the sperm flagellum, as a platform to reinitiate centrosome production. Second, how do most metazoan oocytes manage to build up meiotic spindles without centrosomes? Oocytes have evolved mechanisms to assemble bipolar spindles solely around their chromosomes without the guidance of pre-formed MTOCs. Female animal meiosis involves microtubule nucleation and organisation into bipolar microtubule arrays in regulated self-assembly under the control of the Ran system and nuclear transport receptors. This review summarises our current understanding of the molecular mechanism underlying self-assembly of meiotic spindles, its spatio-temporal regulation, and the key players governing this process in animal oocytes.
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14
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Oocyte stage-specific effects of MTOR determine granulosa cell fate and oocyte quality in mice. Proc Natl Acad Sci U S A 2018; 115:E5326-E5333. [PMID: 29784807 PMCID: PMC6003357 DOI: 10.1073/pnas.1800352115] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
MTOR (mechanistic target of rapamycin), an integrator of pathways important for cellular metabolism, proliferation, and differentiation, is expressed at all stages of oocyte development. Primordial oocytes constitute a nonproliferating, nongrowing reserve of potential eggs maintained for the entire reproductive lifespan of mammalian females. Using conditional knockouts, we determined the role of MTOR in both primordial and growing oocytes. MTOR-dependent pathways in primordial oocytes are not needed to sustain the viability of the primordial oocyte pool or their recruitment into the cohort of growing oocytes but are essential later for maintenance of oocyte genomic integrity, sustaining ovarian follicular development, and fertility. In growing oocytes, MTOR-dependent pathways are required for processes that promote completion of meiosis and enable embryonic development. MTOR (mechanistic target of rapamycin) is a widely recognized integrator of signals and pathways key for cellular metabolism, proliferation, and differentiation. Here we show that conditional knockout (cKO) of Mtor in either primordial or growing oocytes caused infertility but differentially affected oocyte quality, granulosa cell fate, and follicular development. cKO of Mtor in nongrowing primordial oocytes caused defective follicular development leading to progressive degeneration of oocytes and loss of granulosa cell identity coincident with the acquisition of immature Sertoli cell-like characteristics. Although Mtor was deleted at the primordial oocyte stage, DNA damage accumulated in oocytes during their later growth, and there was a marked alteration of the transcriptome in the few oocytes that achieved the fully grown stage. Although oocyte quality and fertility were also compromised when Mtor was deleted after oocytes had begun to grow, these occurred without overtly affecting folliculogenesis or the oocyte transcriptome. Nevertheless, there was a significant change in a cohort of proteins in mature oocytes. In particular, down-regulation of PRC1 (protein regulator of cytokinesis 1) impaired completion of the first meiotic division. Therefore, MTOR-dependent pathways in primordial or growing oocytes differentially affected downstream processes including follicular development, sex-specific identity of early granulosa cells, maintenance of oocyte genome integrity, oocyte gene expression, meiosis, and preimplantation developmental competence.
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Inoue D, Wittbrodt J, Gruss OJ. Loss and Rebirth of the Animal Microtubule Organizing Center: How Maternal Expression of Centrosomal Proteins Cooperates with the Sperm Centriole in Zygotic Centrosome Reformation. Bioessays 2018. [PMID: 29522658 DOI: 10.1002/bies.201700135] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Centrosomes are the main microtubule organizing centers in animal cells. In particular during embryogenesis, they ensure faithful spindle formation and proper cell divisions. As metazoan centrosomes are eliminated during oogenesis, they have to be reassembled upon fertilization. Most metazoans use the sperm centrioles as templates for new centrosome biogenesis while the egg's cytoplasm re-prepares all components for on-going centrosome duplication in rapidly dividing embryonic cells. We discuss our knowledge and the experimental challenges to analyze zygotic centrosome reformation, which requires genetic experiments to enable scrutinizing respective male and female contributions. Male and female knockout animals and mRNA injection to mimic maternal expression of centrosomal proteins could point a way to the systematic molecular dissection of the process. The most recent data suggest that timely expression of centrosome components in oocytes is the key to zygotic centrosome reformation that uses male sperm as coordinators for de novo centrosome production.
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Affiliation(s)
- Daigo Inoue
- Dr. D. Inoue, Prof. Dr. J. Wittbrodt, Centre of Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Joachim Wittbrodt
- Dr. D. Inoue, Prof. Dr. J. Wittbrodt, Centre of Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Oliver J Gruss
- Prof. Dr. O. J. Gruss, Institute of Genetics, University of Bonn, Karlrobert-Kreiten-Str.13, 53115 Bonn, Germany
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Xie B, Zhang L, Zhao H, Bai Q, Fan Y, Zhu X, Yu Y, Li R, Liang X, Sun QY, Li M, Qiao J. Poly(ADP-ribose) mediates asymmetric division of mouse oocyte. Cell Res 2018; 28:462-475. [PMID: 29463901 DOI: 10.1038/s41422-018-0009-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 10/30/2017] [Accepted: 01/05/2018] [Indexed: 11/09/2022] Open
Abstract
Before fertilization, mammalian oocyte undergoes an asymmetric division which depends on eccentric positioning of the spindle at the oocyte cortex to form a polar body and an egg. Since the centriole is absent and, as a result, the polar array microtubules are not fully developed in oocytes, microtubules have seldom been considered as required for eccentric positioning of the spindle, while actin-related forces have instead been proposed to be primarily responsible for this process. However, the existing models are largely conflicting and the underlying mechanism of asymmetric division is still elusive. Here we show that poly(ADP-ribose) (PAR) is enriched at mouse oocyte cortical area throughout meiosis. Specific removal of cortical PAR results in an ectopic spindle and a failure of asymmetric division. During spindle migration, when the spindle deviates from the center of oocyte by a pushing force of cytoplasmic actin, the short polar array microtubules emanating from the juxtacortical spindle pole extend to the cortex and penetrate into cortical PAR, docking and stabilizing the spindle at the cortex which facilitates the asymmetric division. This process depends on the affinity between PAR and microtubule-associated proteins such as Spindly, which contributes to a physical link for cortical PAR and the spindle. Notably, fusing a PAR-binding domain to end-binding protein 3, a plus-end tracking protein at the polar array microtubules, restores the asymmetric division of oocytes with Spindly knockdown. Thus, our work demonstrates a comprehensive mechanism for oocyte spindle positioning and asymmetric division.
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Affiliation(s)
- Bingteng Xie
- Center for Reproductive Medicine, Peking University Third Hospital, 100191, Beijing, China.,Key Laboratory of Assisted Reproduction, Ministry of Education, 100191, Beijing, China
| | - Lu Zhang
- Center for Reproductive Medicine, Peking University Third Hospital, 100191, Beijing, China.,Key Laboratory of Assisted Reproduction, Ministry of Education, 100191, Beijing, China
| | - Huiling Zhao
- School of Basic Medical Sciences, Peking University Health Science Center, 100191, Beijing, China
| | - Qingyun Bai
- School of Basic Medical Sciences, Peking University Health Science Center, 100191, Beijing, China
| | - Yong Fan
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, 510150, Guangzhou, China
| | - Xiaohui Zhu
- Center for Reproductive Medicine, Peking University Third Hospital, 100191, Beijing, China
| | - Yang Yu
- Center for Reproductive Medicine, Peking University Third Hospital, 100191, Beijing, China
| | - Rong Li
- Center for Reproductive Medicine, Peking University Third Hospital, 100191, Beijing, China
| | - Xin Liang
- Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Qing-Yuan Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China
| | - Mo Li
- Center for Reproductive Medicine, Peking University Third Hospital, 100191, Beijing, China. .,Key Laboratory of Assisted Reproduction, Ministry of Education, 100191, Beijing, China.
| | - Jie Qiao
- Center for Reproductive Medicine, Peking University Third Hospital, 100191, Beijing, China. .,Key Laboratory of Assisted Reproduction, Ministry of Education, 100191, Beijing, China.
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