1
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Totsuka T, Akera T, Olson MF. MRCK ensures cortex-chromatin "social distancing" to enable egg spindle rotation. J Cell Biol 2023; 222:e202310009. [PMID: 37843812 PMCID: PMC10579697 DOI: 10.1083/jcb.202310009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023] Open
Abstract
During the second meiotic cell division, egg cells discard one set of chromatids to the polar body to produce a large haploid gamete. Meiotic spindle rotation is a critical step to ensure proper polar body extrusion. In this issue, Bourdais et al. (2023. J. Cell Biol.https://doi.org/10.1083/jcb.202211029) have identified MRCKβ as an essential kinase for efficient spindle rotation. MRCK activates cortical myosin II rings overlying the spindle to prevent the notoriously sticky interaction between the cell cortex and chromatin to facilitate spindle rotation. Furthermore, Bourdais et al. found that the same MRCK-myosin II pathway also operates in zygotes to promote parental genome unification.
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Affiliation(s)
- Takaya Totsuka
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Takashi Akera
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Michael F. Olson
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Canada
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2
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Bourdais A, Dehapiot B, Halet G. MRCK activates mouse oocyte myosin II for spindle rotation and male pronucleus centration. J Cell Biol 2023; 222:e202211029. [PMID: 37651121 PMCID: PMC10470461 DOI: 10.1083/jcb.202211029] [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: 11/08/2022] [Revised: 06/24/2023] [Accepted: 08/09/2023] [Indexed: 09/01/2023] Open
Abstract
Asymmetric meiotic divisions in oocytes rely on spindle positioning in close vicinity to the cortex. In metaphase II mouse oocytes, eccentric spindle positioning triggers cortical polarization, including the build-up of an actin cap surrounded by a ring of activated myosin II. While the role of the actin cap in promoting polar body formation is established, ring myosin II activation mechanisms and functions have remained elusive. Here, we show that ring myosin II activation requires myotonic dystrophy kinase-related Cdc42-binding kinase (MRCK), downstream of polarized Cdc42. MRCK inhibition resulted in spindle rotation defects during anaphase II, precluding polar body extrusion. Remarkably, disengagement of segregated chromatids from the anaphase spindle could rescue rotation. We further show that the MRCK/myosin II pathway is activated in the fertilization cone and is required for male pronucleus migration toward the center of the zygote. These findings provide novel insights into the mechanism of myosin II activation in oocytes and its role in orchestrating asymmetric division and pronucleus centration.
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Affiliation(s)
- Anne Bourdais
- University of Rennes, CNRS - UMR 6290, Institute of Genetics and Development of Rennes, Rennes, France
| | - Benoit Dehapiot
- University of Rennes, CNRS - UMR 6290, Institute of Genetics and Development of Rennes, Rennes, France
| | - Guillaume Halet
- University of Rennes, CNRS - UMR 6290, Institute of Genetics and Development of Rennes, Rennes, France
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3
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Pelzer D, de Plater L, Bradbury P, Eichmuller A, Bourdais A, Halet G, Maître J. Cell fragmentation in mouse preimplantation embryos induced by ectopic activation of the polar body extrusion pathway. EMBO J 2023; 42:e114415. [PMID: 37427462 PMCID: PMC10476277 DOI: 10.15252/embj.2023114415] [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: 05/02/2023] [Revised: 06/13/2023] [Accepted: 06/22/2023] [Indexed: 07/11/2023] Open
Abstract
Cell fragmentation is commonly observed in human preimplantation embryos and is associated with poor prognosis during assisted reproductive technology (ART) procedures. However, the mechanisms leading to cell fragmentation remain largely unknown. Here, light sheet microscopy imaging of mouse embryos reveals that inefficient chromosome separation due to spindle defects, caused by dysfunctional molecular motors Myo1c or dynein, leads to fragmentation during mitosis. Extended exposure of the cell cortex to chromosomes locally triggers actomyosin contractility and pinches off cell fragments. This process is reminiscent of meiosis, during which small GTPase-mediated signals from chromosomes coordinate polar body extrusion (PBE) by actomyosin contraction. By interfering with the signals driving PBE, we find that this meiotic signaling pathway remains active during cleavage stages and is both required and sufficient to trigger fragmentation. Together, we find that fragmentation happens in mitosis after ectopic activation of actomyosin contractility by signals emanating from DNA, similar to those observed during meiosis. Our study uncovers the mechanisms underlying fragmentation in preimplantation embryos and, more generally, offers insight into the regulation of mitosis during the maternal-zygotic transition.
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Affiliation(s)
- Diane Pelzer
- Institut CuriePSL Research University, CNRS UMR 3215, INSERM U934ParisFrance
| | - Ludmilla de Plater
- Institut CuriePSL Research University, CNRS UMR 3215, INSERM U934ParisFrance
| | - Peta Bradbury
- Institut CuriePSL Research University, CNRS UMR 3215, INSERM U934ParisFrance
| | - Adrien Eichmuller
- Institut CuriePSL Research University, CNRS UMR 3215, INSERM U934ParisFrance
| | - Anne Bourdais
- Institut de Génétique et Développement de RennesUniversité de Rennes, CNRS UMR 6290RennesFrance
| | - Guillaume Halet
- Institut de Génétique et Développement de RennesUniversité de Rennes, CNRS UMR 6290RennesFrance
| | - Jean‐Léon Maître
- Institut CuriePSL Research University, CNRS UMR 3215, INSERM U934ParisFrance
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4
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Charalambous C, Webster A, Schuh M. Aneuploidy in mammalian oocytes and the impact of maternal ageing. Nat Rev Mol Cell Biol 2023; 24:27-44. [PMID: 36068367 DOI: 10.1038/s41580-022-00517-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2022] [Indexed: 11/09/2022]
Abstract
During fertilization, the egg and the sperm are supposed to contribute precisely one copy of each chromosome to the embryo. However, human eggs frequently contain an incorrect number of chromosomes - a condition termed aneuploidy, which is much more prevalent in eggs than in either sperm or in most somatic cells. In turn, aneuploidy in eggs is a leading cause of infertility, miscarriage and congenital syndromes. Aneuploidy arises as a consequence of aberrant meiosis during egg development from its progenitor cell, the oocyte. In human oocytes, chromosomes often segregate incorrectly. Chromosome segregation errors increase in women from their mid-thirties, leading to even higher levels of aneuploidy in eggs from women of advanced maternal age, ultimately causing age-related infertility. Here, we cover the two main areas that contribute to aneuploidy: (1) factors that influence the fidelity of chromosome segregation in eggs of women from all ages and (2) factors that change in response to reproductive ageing. Recent discoveries reveal new error-causing pathways and present a framework for therapeutic strategies to extend the span of female fertility.
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Affiliation(s)
- Chloe Charalambous
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Alexandre Webster
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Melina Schuh
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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5
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Simerly CR, Takahashi D, Jacoby E, Castro C, Hartnett C, Hewitson L, Navara C, Schatten G. Fertilization and Cleavage Axes Differ In Primates Conceived By Conventional (IVF) Versus Intracytoplasmic Sperm Injection (ICSI). Sci Rep 2019; 9:15282. [PMID: 31653971 PMCID: PMC6814755 DOI: 10.1038/s41598-019-51815-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 10/03/2019] [Indexed: 12/14/2022] Open
Abstract
With nearly ten million babies conceived globally, using assisted reproductive technologies, fundamental questions remain; e.g., How do the sperm and egg DNA unite? Does ICSI have consequences that IVF does not? Here, pronuclear and mitotic events in nonhuman primate zygotes leading to the establishment of polarity are investigated by multidimensional time-lapse video microscopy and immunocytochemistry. Multiplane videos after ICSI show atypical sperm head displacement beneath the oocyte cortex and eccentric para-tangential pronuclear alignment compared to IVF zygotes. Neither fertilization procedure generates incorporation cones. At first interphase, apposed pronuclei align obliquely to the animal-vegetal axis after ICSI, with asymmetric furrows assembling from the male pronucleus. Furrows form within 30° of the animal pole, but typically, not through the ICSI injection site. Membrane flow drives polar bodies and the ICSI site into the furrow. Mitotic spindle imaging suggests para-tangential pronuclear orientation, which initiates random spindle axes and minimal spindle:cortex interactions. Parthenogenetic pronuclei drift centripetally and assemble astral spindles lacking cortical interactions, leading to random furrows through the animal pole. Conversely, androgenotes display cortex-only pronuclear interactions mimicking ICSI. First cleavage axis determination in primates involves dynamic cortex-microtubule interactions among male pronuclei, centrosomal microtubules, and the animal pole, but not the ICSI site.
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Affiliation(s)
- Calvin R Simerly
- Pittsburgh Development Center, Division of Developmental & Regenerative Medicine, and Obstetrics-Gynecology-Reproductive Sciences, Cell Biology, and Bioengineering, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, 204 Craft Avenue Pittsburgh, Pennsylvania, 15213, USA
| | - Diana Takahashi
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, 97006, USA
| | - Ethan Jacoby
- CCRM Houston Main Center Memorial City, 929 Gessner Rd, Suite 2300, Houston, Texas, 77024, USA
| | - Carlos Castro
- Pittsburgh Development Center, Division of Developmental & Regenerative Medicine, and Obstetrics-Gynecology-Reproductive Sciences, Cell Biology, and Bioengineering, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, 204 Craft Avenue Pittsburgh, Pennsylvania, 15213, USA
| | - Carrie Hartnett
- Pittsburgh Development Center, Division of Developmental & Regenerative Medicine, and Obstetrics-Gynecology-Reproductive Sciences, Cell Biology, and Bioengineering, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, 204 Craft Avenue Pittsburgh, Pennsylvania, 15213, USA
| | - Laura Hewitson
- The Johnson Center for Child Health and Development, Austin, Texas, 78701, USA
| | - Christopher Navara
- Department of Biology, South Texas Center for Emerging Infectious Disease, University of Texas at San Antonio, San Antonio, Texas, 78249, USA
| | - Gerald Schatten
- Pittsburgh Development Center, Division of Developmental & Regenerative Medicine, and Obstetrics-Gynecology-Reproductive Sciences, Cell Biology, and Bioengineering, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, 204 Craft Avenue Pittsburgh, Pennsylvania, 15213, USA.
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6
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Zhang Y, Wan X, Wang HH, Pan MH, Pan ZN, Sun SC. RAB35 depletion affects spindle formation and actin-based spindle migration in mouse oocyte meiosis. ACTA ACUST UNITED AC 2019; 25:359-372. [DOI: 10.1093/molehr/gaz027] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/28/2019] [Accepted: 05/17/2019] [Indexed: 12/16/2022]
Abstract
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.
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Affiliation(s)
- Yu Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Xiang Wan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Hong-Hui Wang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Meng-Hao Pan
- 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
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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7
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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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8
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Abstract
Fertilizable eggs develop from diploid precursor cells termed oocytes. Once every menstrual cycle, an oocyte matures into a fertilizable egg in the ovary. To this end, the oocyte eliminates half of its chromosomes into a small cell termed a polar body. The egg is then released into the Fallopian tube, where it can be fertilized. Upon fertilization, the egg completes the second meiotic division, and the mitotic division of the embryo starts. This review highlights recent work that has shed light on the cytoskeletal structures that drive the meiotic divisions of the oocyte in mammals. In particular, we focus on how mammalian oocytes assemble a microtubule spindle in the absence of centrosomes, how they position the spindle in preparation for polar body extrusion, and how the spindle segregates the chromosomes. We primarily focus on mouse oocytes as a model system but also highlight recent insights from human oocytes.
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Affiliation(s)
- Binyam Mogessie
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
- Current affiliation: School of Biochemistry, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Kathleen Scheffler
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
| | - Melina Schuh
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
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9
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Duan X, Sun SC. Actin cytoskeleton dynamics in mammalian oocyte meiosis†. Biol Reprod 2018; 100:15-24. [DOI: 10.1093/biolre/ioy163] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 07/11/2018] [Indexed: 12/12/2022] Open
Affiliation(s)
- Xing Duan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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10
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Martin JH, Bromfield EG, Aitken RJ, Nixon B. Biochemical alterations in the oocyte in support of early embryonic development. Cell Mol Life Sci 2017; 74:469-485. [PMID: 27604868 PMCID: PMC11107538 DOI: 10.1007/s00018-016-2356-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/28/2016] [Accepted: 09/01/2016] [Indexed: 01/01/2023]
Abstract
Notwithstanding the enormous reproductive potential encapsulated within a mature mammalian oocyte, these cells present only a limited window for fertilization before defaulting to an apoptotic cascade known as post-ovulatory oocyte aging. The only cell with the capacity to rescue this potential is the fertilizing spermatozoon. Indeed, the union of these cells sets in train a remarkable series of events that endows the oocyte with the capacity to divide and differentiate into the trillions of cells that comprise a new individual. Traditional paradigms hold that, beyond the initial stimulation of fluctuating calcium (Ca2+) required for oocyte activation, the fertilizing spermatozoon plays limited additional roles in the early embryo. While this model has now been drawn into question in view of the recent discovery that spermatozoa deliver developmentally important classes of small noncoding RNAs and other epigenetic modulators to oocytes during fertilization, it is nevertheless apparent that the primary responsibility for oocyte activation rests with a modest store of maternally derived proteins and mRNA accumulated during oogenesis. It is, therefore, not surprising that widespread post-translational modifications, in particular phosphorylation, hold a central role in endowing these proteins with sufficient functional diversity to initiate embryonic development. Indeed, proteins targeted for such modifications have been linked to oocyte activation, recruitment of maternal mRNAs, DNA repair and resumption of the cell cycle. This review, therefore, seeks to explore the intimate relationship between Ca2+ release and the suite of molecular modifications that sweep through the oocyte to ensure the successful union of the parental germlines and ensure embryogenic fidelity.
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Affiliation(s)
- Jacinta H Martin
- Discipline of Biological Sciences and Priority Research Center for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia.
| | - Elizabeth G Bromfield
- Discipline of Biological Sciences and Priority Research Center for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
| | - R John Aitken
- Discipline of Biological Sciences and Priority Research Center for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
| | - Brett Nixon
- Discipline of Biological Sciences and Priority Research Center for Reproductive Science, School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
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11
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Chaigne A, Terret ME, Verlhac MH. Asymmetries and Symmetries in the Mouse Oocyte and Zygote. Results Probl Cell Differ 2017; 61:285-299. [PMID: 28409310 DOI: 10.1007/978-3-319-53150-2_13] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mammalian oocytes grow periodically after puberty thanks to the dialogue with their niche in the follicle. This communication between somatic and germ cells promotes the accumulation, inside the oocyte, of maternal RNAs, proteins and other molecules that will sustain the two gamete divisions and early embryo development up to its implantation. In order to preserve their stock of maternal products, oocytes from all species divide twice minimizing the volume of their daughter cells to their own benefit. For this, they undergo asymmetric divisions in size where one main objective is to locate the division spindle with its chromosomes off-centred. In this chapter, we will review how this main objective is reached with an emphasis on the role of actin microfilaments in this process in mouse oocytes, the most studied example in mammals. This chapter is subdivided into three parts: I-General features of asymmetric divisions in mouse oocytes, II-Mechanism of chromosome positioning by actin in mouse oocytes and III-Switch from asymmetric to symmetric division at the oocyte-to-embryo transition.
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Affiliation(s)
- Agathe Chaigne
- MRC Laboratory for Molecular Cell Biology, UCL, London, WC1E 6BT, UK.,Institute for the Physics of Living Systems, UCL, London, WC1E 6BT, UK
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12
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Nannas NJ, Higgins DM, Dawe RK. Anaphase asymmetry and dynamic repositioning of the division plane during maize meiosis. J Cell Sci 2016; 129:4014-4024. [PMID: 27609836 DOI: 10.1242/jcs.194860] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 09/05/2016] [Indexed: 01/12/2023] Open
Abstract
The success of an organism is contingent upon its ability to transmit genetic material through meiotic cell division. In plant meiosis I, the process begins in a large spherical cell without physical cues to guide the process. Yet, two microtubule-based structures, the spindle and phragmoplast, divide the chromosomes and the cell with extraordinary accuracy. Using a live-cell system and fluorescently labeled spindles and chromosomes, we found that the process self- corrects as meiosis proceeds. Metaphase spindles frequently initiate division off-center, and in these cases anaphase progression is asymmetric with the two masses of chromosomes traveling unequal distances on the spindle. The asymmetry is compensatory, such that the chromosomes on the side of the spindle that is farthest from the cell cortex travel a longer distance at a faster rate. The phragmoplast forms at an equidistant point between the telophase nuclei rather than at the original spindle mid-zone. This asymmetry in chromosome movement implies a structural difference between the two halves of a bipolar spindle and could allow meiotic cells to dynamically adapt to errors in metaphase and accurately divide the cell volume.
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Affiliation(s)
- Natalie J Nannas
- Department of Plant Biology, University of Georgia, Athens, GA 30605, USA
| | - David M Higgins
- Department of Plant Biology, University of Georgia, Athens, GA 30605, USA
| | - R Kelly Dawe
- Department of Plant Biology, University of Georgia, Athens, GA 30605, USA .,Department of Genetics, University of Georgia, Athens, GA 30605, USA
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13
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Chen L, Zhai L, Qu C, Zhang C, Li S, Wu F, Qi Y, Lu F, Xu P, Li X, Shi D. Comparative Proteomic Analysis of Buffalo Oocytes Matured in vitro Using iTRAQ Technique. Sci Rep 2016; 6:31795. [PMID: 27561356 PMCID: PMC4999887 DOI: 10.1038/srep31795] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 07/26/2016] [Indexed: 12/11/2022] Open
Abstract
To investigate the protein profiling of buffalo oocytes at the germinal vesicle (GV) stage and metaphase II (MII) stage, an iTRAQ-based strategy was applied. A total of 3,763 proteins were identified, which representing the largest buffalo oocytes proteome dataset to date. Among these proteins identified, 173 proteins were differentially expressed in GV oocytes and competent MII oocytes, and 146 proteins were differentially abundant in competent and incompetent matured oocytes. Functional and KEGG pathway analysis revealed that the up-regulated proteins in competent MII oocytes were related to chromosome segregation, microtubule-based process, protein transport, oxidation reduction, ribosome, and oxidative phosphorylation, etc., in comparison with GV and incompetent MII oocytes. This is the first proteomic report on buffalo oocytes from different maturation stages and developmental competent status. These data will provide valuable information for understanding the molecular mechanism underlying buffalo oocyte maturation, and these proteins may potentially act as markers to predict developmental competence of buffalo oocyte during in vitro maturation.
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Affiliation(s)
- Lingsheng Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530005, China.,State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Engineering Research Center for Protein Drugs, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing 102206, China
| | - Linhui Zhai
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Engineering Research Center for Protein Drugs, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing 102206, China.,Chemical Proteomics Center &State Key Laboratory of Drug Research, Shanghai Institute of Materia Medical, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Chunfeng Qu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530005, China.,Department of reproductive medicine, Hechi People's hospital of Guangxi, Hechi 547000, China
| | - Chengpu Zhang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Engineering Research Center for Protein Drugs, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing 102206, China
| | - Sheng Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530005, China
| | - Feilin Wu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Engineering Research Center for Protein Drugs, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing 102206, China
| | - Yingzi Qi
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Engineering Research Center for Protein Drugs, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing 102206, China
| | - Fenghua Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530005, China
| | - Ping Xu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Engineering Research Center for Protein Drugs, National Center for Protein Sciences, Beijing Institute of Radiation Medicine, Beijing 102206, China.,Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China
| | - Xiangping Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530005, China
| | - Deshun Shi
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530005, China
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14
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Namgoong S, Kim NH. Roles of actin binding proteins in mammalian oocyte maturation and beyond. Cell Cycle 2016; 15:1830-43. [PMID: 27152960 DOI: 10.1080/15384101.2016.1181239] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Actin nucleation factors, which promote the formation of new actin filaments, have emerged in the last decade as key regulatory factors controlling asymmetric division in mammalian oocytes. Actin nucleators such as formin-2, spire, and the ARP2/3 complex have been found to be important regulators of actin remodeling during oocyte maturation. Another class of actin-binding proteins including cofilin, tropomyosin, myosin motors, capping proteins, tropomodulin, and Ezrin-Radixin-Moesin proteins are thought to control actin cytoskeleton dynamics at various steps of oocyte maturation. In addition, actin dynamics controlling asymmetric-symmetric transitions after fertilization is a new area of investigation. Taken together, defining the mechanisms by which actin-binding proteins regulate actin cytoskeletons is crucial for understanding the basic biology of mammalian gamete formation and pre-implantation development.
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Affiliation(s)
- Suk Namgoong
- a Department of Animal Sciences , Chungbuk National University , Cheong-Ju , ChungChungBuk-do , Republic of Korea
| | - Nam-Hyung Kim
- a Department of Animal Sciences , Chungbuk National University , Cheong-Ju , ChungChungBuk-do , Republic of Korea
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15
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Zhang Y, Stefanovic B. LARP6 Meets Collagen mRNA: Specific Regulation of Type I Collagen Expression. Int J Mol Sci 2016; 17:419. [PMID: 27011170 PMCID: PMC4813270 DOI: 10.3390/ijms17030419] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/15/2016] [Accepted: 03/17/2016] [Indexed: 01/15/2023] Open
Abstract
Type I collagen is the most abundant structural protein in all vertebrates, but its constitutive rate of synthesis is low due to long half-life of the protein (60-70 days). However, several hundred fold increased production of type I collagen is often seen in reparative or reactive fibrosis. The mechanism which is responsible for this dramatic upregulation is complex, including multiple levels of regulation. However, posttranscriptional regulation evidently plays a predominant role. Posttranscriptional regulation comprises processing, transport, stabilization and translation of mRNAs and is executed by RNA binding proteins. There are about 800 RNA binding proteins, but only one, La ribonucleoprotein domain family member 6 (LARP6), is specifically involved in type I collagen regulation. In the 5'untranslated region (5'UTR) of mRNAs encoding for type I and type III collagens there is an evolutionally conserved stem-loop (SL) structure; this structure is not found in any other mRNA, including any other collagen mRNA. LARP6 binds to the 5'SL in sequence specific manner to regulate stability of collagen mRNAs and their translatability. Here, we will review current understanding of how is LARP6 involved in posttranscriptional regulation of collagen mRNAs. We will also discuss how other proteins recruited by LARP6, including nonmuscle myosin, vimentin, serine threonine kinase receptor associated protein (STRAP), 25 kD FK506 binding protein (FKBP25) and RNA helicase A (RHA), contribute to this process.
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Affiliation(s)
- Yujie Zhang
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA.
| | - Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA.
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16
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Chaigne A, Campillo C, Voituriez R, Gov NS, Sykes C, Verlhac MH, Terret ME. F-actin mechanics control spindle centring in the mouse zygote. Nat Commun 2016; 7:10253. [PMID: 26727405 PMCID: PMC4725770 DOI: 10.1038/ncomms10253] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/20/2015] [Indexed: 01/01/2023] Open
Abstract
Mitotic spindle position relies on interactions between astral microtubules nucleated by centrosomes and a rigid cortex. Some cells, such as mouse oocytes, do not possess centrosomes and astral microtubules. These cells rely only on actin and on a soft cortex to position their spindle off-centre and undergo asymmetric divisions. While the first mouse embryonic division also occurs in the absence of centrosomes, it is symmetric and not much is known on how the spindle is positioned at the exact cell centre. Using interdisciplinary approaches, we demonstrate that zygotic spindle positioning follows a three-step process: (1) coarse centring of pronuclei relying on the dynamics of an F-actin/Myosin-Vb meshwork; (2) fine centring of the metaphase plate depending on a high cortical tension; (3) passive maintenance at the cell centre. Altogether, we show that F-actin-dependent mechanics operate the switch between asymmetric to symmetric division required at the oocyte to embryo transition.
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Affiliation(s)
- Agathe Chaigne
- CIRB, Collège de France, and CNRS-UMR7241 and INSERM-U1050, Equipe labellisée Ligue contre le Cancer, Paris F-75005, France
| | - Clément Campillo
- Université Evry Val d'Essonne, LAMBE, Boulevard F Mitterrand, Evry 91025, France
| | | | - Nir S Gov
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Cécile Sykes
- CNRS-UMR168, Paris F-75248, France.,UPMC, 4 Place Jussieu, Paris F-75248, France.,Institut Curie, Centre de Recherche, Laboratoire Physico-Chimie, Paris F-75248, France
| | - Marie-Hélène Verlhac
- CIRB, Collège de France, and CNRS-UMR7241 and INSERM-U1050, Equipe labellisée Ligue contre le Cancer, Paris F-75005, France
| | - Marie-Emilie Terret
- CIRB, Collège de France, and CNRS-UMR7241 and INSERM-U1050, Equipe labellisée Ligue contre le Cancer, Paris F-75005, France
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17
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Li YR, Yang WX. Myosin superfamily: The multi-functional and irreplaceable factors in spermatogenesis and testicular tumors. Gene 2015; 576:195-207. [PMID: 26478466 DOI: 10.1016/j.gene.2015.10.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 09/21/2015] [Accepted: 10/12/2015] [Indexed: 10/22/2022]
Abstract
Spermatogenesis is a fundamental process in sexual development and reproduction, in which the diploid spermatogonia transform into haploid mature spermatozoa. This process is under the regulation of multiple factors and pathway. Myosin has been implicated in various aspects during spermatogenesis. Myosins constitute a diverse superfamily of actin-based molecular motors that translocate along microfilament in an ATP-dependent manner, and six kinds of myosins have been proved that function during spermatogenesis. In mitosis and meiosis, myosins play an important role in spindle assembly and positioning, karyokinesis and cytokinesis. During spermiogenesis, myosins participate in acrosomal formation, nuclear morphogenesis, mitochondrial translocation and spermatid individualization. In this review, we summarize current understanding of the functions of myosin in spermatogenesis and some reproductive system diseases such as testicular tumors and prostate cancer, and discuss the roles of possible upstream molecules which regulate myosin in these processes.
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Affiliation(s)
- Yan-Ruide Li
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
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18
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Ozkan ED, Aceti M, Creson TK, Rojas CS, Hubbs CR, McGuire MN, Kakad PP, Miller CA, Rumbaugh G. Input-specific regulation of hippocampal circuit maturation by non-muscle myosin IIB. J Neurochem 2015; 134:429-44. [PMID: 25931194 DOI: 10.1111/jnc.13146] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 04/04/2015] [Accepted: 04/08/2015] [Indexed: 12/18/2022]
Abstract
Myh9 and Myh10, which encode two major isoforms of non-muscle myosin II expressed in the brain, have emerged as risk factors for developmental brain disorders. Myosin II motors regulate neuronal cytoskeletal dynamics leading to optimization of synaptic plasticity and memory formation. However, the role of these motor complexes in brain development remains poorly understood. Here, we disrupted the in vivo expression of Myh9 and/or Myh10 in developing hippocampal neurons to determine how these motors contribute to circuit maturation in this brain area important for cognition. We found that Myh10 ablation in early postnatal, but not mature, CA1 pyramidal neurons reduced excitatory synaptic function in the Schaffer collateral pathway, whereas more distal inputs to CA1 neurons were relatively unaffected. Myh10 ablation in young neurons also selectively impaired the elongation of oblique dendrites that receive Schaffer collateral inputs, whereas the structure of distal dendrites was normal. We observed normal spine density and spontaneous excitatory currents in these neurons, indicating that Myh10 KO impaired proximal pathway synaptic maturation through disruptions to dendritic development rather than post-synaptic strength or spine morphogenesis. To address possible redundancy and/or compensation by other Myosin II motors expressed in neurons, we performed similar experiments in Myh9 null neurons. In contrast to findings in Myh10 mutants, evoked synaptic function in young Myh9 KO hippocampal neurons was normal. Data obtained from double Myh9/Myh10 KO neurons largely resembled the MyH10 KO synaptic phenotype. These data indicate that Myosin IIB is a key molecular factor that guides input-specific circuit maturation in the developing hippocampus. Non-muscle myosin II is an actin binding protein with three isoforms in the brain (IIA, IIB and IIC) encoded by the myh9, myh10, and myh14 genes in mice, respectively. We have studied the structure and the function of hippocampal CA1 neurons missing NMIIB and/or NMIIA proteins at different times during development. We have discovered that NMIIB is the major isoform regulating Schaffer collateral inputs, and that this regulation is restricted to early postnatal development.
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Affiliation(s)
- Emin D Ozkan
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
| | - Massimiliano Aceti
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
| | - Thomas K Creson
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
| | - Camilo S Rojas
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
| | - Christopher R Hubbs
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
| | - Megan N McGuire
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
| | - Priyanka P Kakad
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida, USA
| | - Courtney A Miller
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA.,Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, Florida, USA
| | - Gavin Rumbaugh
- Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida, USA
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19
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McGinnis LA, Lee HJ, Robinson DN, Evans JP. MAPK3/1 (ERK1/2) and Myosin Light Chain Kinase in Mammalian Eggs Affect Myosin-II Function and Regulate the Metaphase II State in a Calcium- and Zinc-Dependent Manner. Biol Reprod 2015; 92:146. [PMID: 25904014 DOI: 10.1095/biolreprod.114.127027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 04/16/2015] [Indexed: 12/25/2022] Open
Abstract
Vertebrate eggs are arrested at metaphase of meiosis II, a state classically known as cytostatic factor arrest. Maintenance of this arrest until the time of fertilization and then fertilization-induced exit from metaphase II are crucial for reproductive success. Another key aspect of this meiotic arrest and exit is regulation of the metaphase II spindle, which must be appropriately localized adjacent to the egg cortex during metaphase II and then progress into successful asymmetric cytokinesis to produce the second polar body. This study examined the mitogen-activated protein kinases MAPK3 and MAPK1 (also known as ERK1/2) as regulators of these two related aspects of mammalian egg biology, specifically testing whether this MAPK pathway affected myosin-II function and whether myosin-II perturbation would produce some of the same effects as MAPK pathway perturbation. Inhibition of the MEK1/2-MAPK pathway with U0126 leads to reduced levels of phosphorylated myosin-regulatory light chain (pMRLC) and causes a reduction in cortical tension, effects that are mimicked by treatment with the myosin light chain kinase (MLCK) inhibitor ML-7. These data indicate that one mechanism by which the MAPK pathway acts in eggs is by affecting myosin-II function. We further show that MAPK or MLCK inhibition induces loss of normal cortical spindle localization or parthenogenetic egg activation. This parthenogenesis is dependent on cytosolic and extracellular calcium and can be rescued by hyperloading eggs with zinc, suggesting that these effects of inhibition of MLCK or the MAPK pathway are linked with dysregulation of ion homeostasis.
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Affiliation(s)
- Lauren A McGinnis
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Hyo J Lee
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Douglas N Robinson
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Janice P Evans
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
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20
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Liang QX, Zhang QH, Qi ST, Wang ZW, Hu MW, Ma XS, Zhu MS, Schatten H, Wang ZB, Sun QY. Deletion of Mylk1 in Oocytes Causes Delayed Morula-to-Blastocyst Transition and Reduced Fertility Without Affecting Folliculogenesis and Oocyte Maturation in Mice1. Biol Reprod 2015; 92:97. [DOI: 10.1095/biolreprod.114.122127] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 03/06/2015] [Indexed: 01/10/2023] Open
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21
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Sharif B, Fadero T, Maddox AS. Anillin localization suggests distinct mechanisms of division plane specification in mouse oogenic meiosis I and II. Gene Expr Patterns 2015; 17:98-106. [PMID: 25818309 DOI: 10.1016/j.gep.2015.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 03/05/2015] [Accepted: 03/13/2015] [Indexed: 01/22/2023]
Abstract
Anillin is a conserved cytokinetic ring protein implicated in actomyosin cytoskeletal organization and cytoskeletal-membrane linkage. Here we explored anillin localization in the highly asymmetric divisions of the mouse oocyte that lead to the extrusion of two polar bodies. The purposes of polar body extrusion are to reduce the chromosome complement within the egg to haploid, and to retain the majority of the egg cytoplasm for embryonic development. Anillin's proposed roles in cytokinetic ring organization suggest that it plays important roles in achieving this asymmetric division. We report that during meiotic maturation, anillin mRNA is expressed and protein levels steadily rise. In meiosis I, anillin localizes to a cortical cap overlying metaphase I spindles, and a broad ring over anaphase spindles that are perpendicular to the cortex. Anillin is excluded from the cortex of the prospective first polar body, and highly enriched in the cytokinetic ring that severs the polar body from the oocyte. In meiosis II, anillin is enriched in a cortical stripe precisely coincident with and overlying the meiotic spindle midzone. These results suggest a model in which this cortical structure contributes to spindle re-alignment in meiosis II. Thus, localization of anillin as a conserved cytokinetic ring marker illustrates that the geometry of the cytokinetic ring is distinct between the two oogenic meiotic cytokineses in mammals.
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Affiliation(s)
- Bedra Sharif
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, Canada
| | - Tanner Fadero
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
| | - Amy Shaub Maddox
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA.
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22
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A narrow window of cortical tension guides asymmetric spindle positioning in the mouse oocyte. Nat Commun 2015; 6:6027. [PMID: 25597399 DOI: 10.1038/ncomms7027] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 12/02/2014] [Indexed: 01/17/2023] Open
Abstract
Cell mechanics control the outcome of cell division. In mitosis, external forces applied on a stiff cortex direct spindle orientation and morphogenesis. During oocyte meiosis on the contrary, spindle positioning depends on cortex softening. How changes in cortical organization induce cortex softening has not yet been addressed. Furthermore, the range of tension that allows spindle migration remains unknown. Here, using artificial manipulation of mouse oocyte cortex as well as theoretical modelling, we show that cortical tension has to be tightly regulated to allow off-center spindle positioning: a too low or too high cortical tension both lead to unsuccessful spindle migration. We demonstrate that the decrease in cortical tension required for spindle positioning is fine-tuned by a branched F-actin network that triggers the delocalization of myosin-II from the cortex, which sheds new light on the interplay between actin network architecture and cortex tension.
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23
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Wang H, Stefanovic B. Role of LARP6 and nonmuscle myosin in partitioning of collagen mRNAs to the ER membrane. PLoS One 2014; 9:e108870. [PMID: 25271881 PMCID: PMC4182744 DOI: 10.1371/journal.pone.0108870] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 09/01/2014] [Indexed: 02/07/2023] Open
Abstract
Type I collagen is extracellular matrix protein composed of two α1(I) and one α2(I) polypeptides that fold into triple helix. Collagen polypeptides are translated in coordination to synchronize the rate of triple helix folding to the rate of posttranslational modifications of individual polypeptides. This is especially important in conditions of high collagen production, like fibrosis. It has been assumed that collagen mRNAs are targeted to the membrane of the endoplasmic reticulum (ER) after translation of the signal peptide and by signal peptide recognition particle (SRP). Here we show that collagen mRNAs associate with the ER membrane even when translation is inhibited. Knock down of LARP6, an RNA binding protein which binds 5' stem-loop of collagen mRNAs, releases a small amount of collagen mRNAs from the membrane. Depolimerization of nonmuscle myosin filaments has a similar, but stronger effect. In the absence of LARP6 or nonmuscle myosin filaments collagen polypeptides become hypermodified, are poorly secreted and accumulate in the cytosol. This indicates lack of coordination of their synthesis and retro-translocation due to hypermodifications and misfolding. Depolimerization of nonmuscle myosin does not alter the secretory pathway through ER and Golgi, suggesting that the role of nonmuscle myosin is primarily to partition collagen mRNAs to the ER membrane. We postulate that collagen mRNAs directly partition to the ER membrane prior to synthesis of the signal peptide and that LARP6 and nonmuscle myosin filaments mediate this process. This allows coordinated initiation of translation on the membrane bound collagen α1(I) and α2(I) mRNAs, a necessary step for proper synthesis of type I collagen.
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Affiliation(s)
- Hao Wang
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, United States of America
| | - Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, United States of America
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24
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Chaigne A, Verlhac MH, Terret ME. [Cortex softening: a prerequisite for the asymmetry of oocyte first division]. Med Sci (Paris) 2014; 30:18-21. [PMID: 24472451 DOI: 10.1051/medsci/20143001005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Agathe Chaigne
- Centre interdisciplinaire de recherche en biologie, CNRS-UMR7241, Inserm-U1050, Équipe labellisée Ligue contre le cancer, Collège de France, 11, place Marcelin Berthelot, 75005 Paris, France - Memolife Laboratory of Excellence and Paris Science Lettre, Paris, F-75005, France
| | - Marie-Hélène Verlhac
- Centre interdisciplinaire de recherche en biologie, CNRS-UMR7241, Inserm-U1050, Équipe labellisée Ligue contre le cancer, Collège de France, 11, place Marcelin Berthelot, 75005 Paris, France - Memolife Laboratory of Excellence and Paris Science Lettre, Paris, F-75005, France
| | - Marie-Emilie Terret
- Centre interdisciplinaire de recherche en biologie, CNRS-UMR7241, Inserm-U1050, Équipe labellisée Ligue contre le cancer, Collège de France, 11, place Marcelin Berthelot, 75005 Paris, France - Memolife Laboratory of Excellence and Paris Science Lettre, Paris, F-75005, France
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25
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Stefanovic B. RNA protein interactions governing expression of the most abundant protein in human body, type I collagen. WILEY INTERDISCIPLINARY REVIEWS. RNA 2013; 4:535-45. [PMID: 23907854 PMCID: PMC3748166 DOI: 10.1002/wrna.1177] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Type I collagen is the most abundant protein in human body. The protein turns over slowly and its replacement synthesis is low. However, in wound healing or in pathological fibrosis the cells can increase production of type I collagen several hundred fold. This increase is predominantly due to posttranscriptional regulation, including increased half-life of collagen messenger RNAs (mRNAs) and their increased translatability. Type I collagen is composed of two α1 and one α2 polypeptides that fold into a triple helix. This stoichiometry is strictly regulated to prevent detrimental synthesis of α1 homotrimers. Collagen polypeptides are co-translationally modified and the rate of modifications is in dynamic equilibrium with the rate of folding, suggesting coordinated translation of collagen α1(I) and α2(I) polypeptides. Collagen α1(I) mRNA has in the 3' untranslated region (UTR) a C-rich sequence that binds protein αCP, this binding stabilizes the mRNA in collagen producing cells. In the 5' UTR both collagen mRNAs have a conserved stem-loop (5' SL) structure. The 5' SL is critical for high collagen expression, knock in mice with disruption of the 5' SL are resistant to liver fibrosis. the 5' SL binds protein LARP6 with strict sequence specificity and high affinity. LARP6 recruits RNA helicase A to facilitate translation initiation and associates collagen mRNAs with vimentin and nonmuscle myosin filaments. Binding to vimentin stabilizes collagen mRNAs, while nonmuscle myosin regulates coordinated translation of α1(I) and α2(I) mRNAs. When nonmuscle myosin filaments are disrupted the cells secrete only α1 homotrimers. Thus, the mechanism governing high collagen expression involves two RNA binding proteins and development of cytoskeletal filaments.
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Affiliation(s)
- Branko Stefanovic
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA.
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26
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Sun SC, Kim NH. Molecular mechanisms of asymmetric division in oocytes. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2013; 19:883-897. [PMID: 23764118 DOI: 10.1017/s1431927613001566] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In contrast to symmetric division in mitosis, mammalian oocyte maturation is characterized by asymmetric cell division that produces a large egg and a small polar body. The asymmetry results from oocyte polarization, which includes spindle positioning, migration, and cortical reorganization, and this process is critical for fertilization and the retention of maternal components for early embryo development. Although actin dynamics are involved in this process, the molecular mechanism underlying this remained unclear until the use of confocal microscopy and live cell imaging became widespread in recent years. Information obtained through a PubMed database search of all articles published in English between 2000 and 2012 that included the phrases "oocyte, actin, spindle migration," "oocyte, actin, polar body," or "oocyte, actin, asymmetric division" was reviewed. The actin nucleation factor actin-related protein 2/3 complex and its nucleation-promoting factors, formins and Spire, and regulators such as small GTPases, partitioning-defective/protein kinase C, Fyn, microRNAs, cis-Golgi apparatus components, myosin/myosin light-chain kinase, spindle stability regulators, and spindle assembly checkpoint regulators, play critical roles in asymmetric cell division in oocytes. This review summarizes recent findings on these actin-related regulators in mammalian oocyte asymmetric division and outlines a complete signaling pathway.
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Affiliation(s)
- Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
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27
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A soft cortex is essential for asymmetric spindle positioning in mouse oocytes. Nat Cell Biol 2013; 15:958-66. [PMID: 23851486 DOI: 10.1038/ncb2799] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 06/03/2013] [Indexed: 12/19/2022]
Abstract
At mitosis onset, cortical tension increases and cells round up, ensuring correct spindle morphogenesis and orientation. Thus, cortical tension sets up the geometric requirements of cell division. On the contrary, cortical tension decreases during meiotic divisions in mouse oocytes, a puzzling observation because oocytes are round cells, stable in shape, that actively position their spindles. We investigated the pathway leading to reduction in cortical tension and its significance for spindle positioning. We document a previously uncharacterized Arp2/3-dependent thickening of the cortical F-actin essential for first meiotic spindle migration to the cortex. Using micropipette aspiration, we show that cortical tension decreases during meiosis I, resulting from myosin-II exclusion from the cortex, and that cortical F-actin thickening promotes cortical plasticity. These events soften and relax the cortex. They are triggered by the Mos-MAPK pathway and coordinated temporally. Artificial cortex stiffening and theoretical modelling demonstrate that a soft cortex is essential for meiotic spindle positioning.
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28
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Dehapiot B, Carrière V, Carroll J, Halet G. Polarized Cdc42 activation promotes polar body protrusion and asymmetric division in mouse oocytes. Dev Biol 2013; 377:202-12. [PMID: 23384564 PMCID: PMC3690527 DOI: 10.1016/j.ydbio.2013.01.029] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 12/22/2012] [Accepted: 01/25/2013] [Indexed: 11/28/2022]
Abstract
Asymmetric meiotic divisions in mammalian oocytes rely on the eccentric positioning of the spindle and the remodeling of the overlying cortex, resulting in the formation of small polar bodies. The mechanism of this cortical polarization, exemplified by the formation of a thick F-actin cap, is poorly understood. Cdc42 is a major player in cell polarization in many systems; however, the spatio-temporal dynamics of Cdc42 activation during oocyte meiosis, and its contribution to mammalian oocyte polarization, have remained elusive. In this study, we investigated Cdc42 activation (Cdc42–GTP), dynamics and role during mouse oocyte meiotic divisions. We show that Cdc42–GTP accumulates in restricted cortical regions overlying meiotic chromosomes or chromatids, in a Ran–GTP-dependent manner. This polarized activation of Cdc42 is required for the recruitment of N-WASP and the formation of F-actin-rich protrusions during polar body formation. Cdc42 inhibition in MII oocytes resulted in the release of N-WASP into the cytosol, a loss of the polarized F-actin cap, and a failure to protrude the second polar body. Cdc42 inhibition also resulted in central spindle defects in activated MII oocytes. In contrast, emission of the first polar body during oocyte maturation could occur in the absence of a functional Cdc42/N-WASP pathway. Therefore, Cdc42 is a new protagonist in chromatin-induced cortical polarization in mammalian oocytes, with an essential role in meiosis II completion, through the recruitment and activation of N-WASP, downstream of the chromatin-centered Ran–GTP gradient.
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Affiliation(s)
- Benoit Dehapiot
- CNRS, UMR 6290, Institut de Génétique et Développement de Rennes, F-35043 Rennes, France
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29
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Maddox AS, Azoury J, Dumont J. Polar body cytokinesis. Cytoskeleton (Hoboken) 2012; 69:855-68. [PMID: 22927361 DOI: 10.1002/cm.21064] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Accepted: 08/20/2012] [Indexed: 02/04/2023]
Abstract
Polar body cytokinesis is the physical separation of a small polar body from a larger oocyte or ovum. This maternal meiotic division shares many similarities with mitotic and spermatogenic cytokinesis, but there are several distinctions, which will be discussed in this review. We synthesize results from many different model species, including those popular for their genetics and several that are more obscure in modern cell biology. The site of polar body division is determined before anaphase, by the eccentric, cortically associated meiotic spindle. Depending on the species, either the actin or microtubule cytoskeleton is required for spindle anchoring. Chromatin is necessary and sufficient to elicit differentiation of the associated cortex, via Ran-based signaling. The midzone of the anaphase spindle serves as a hub for regulatory complexes that elicit Rho activation, and ultimately actomyosin contractile ring assembly and contraction. Polar body cytokinesis uniquely requires another Rho family GTPase, Cdc42, for dynamic reorganization of the polar cortex. This is perhaps due to the considerable asymmetry of this division, wherein the polar body and the oocyte/ovum have distinct fates and very different sizes. Thus, maternal meiotic cytokinesis appears to occur via simultaneous polar relaxation and equatorial contraction, since the polar body is extruded from the spherical oocyte through the nascent contractile ring. As such, polar body cytokinesis is an interesting and important variation on the theme of cell division.
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Affiliation(s)
- Amy Shaub Maddox
- Institut de recherche en immunology et en cancerologie (IRIC), Université de Montréal, Montréal, Quebec, Canada.
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30
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Yang F, Wei Q, Adelstein RS, Wang PJ. Non-muscle myosin IIB is essential for cytokinesis during male meiotic cell divisions. Dev Biol 2012; 369:356-61. [PMID: 22820068 DOI: 10.1016/j.ydbio.2012.07.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 07/12/2012] [Accepted: 07/13/2012] [Indexed: 12/26/2022]
Abstract
Cytokinesis, the final stage of cell division, bisects the cytoplasm into two daughter cells. In mitotic cells, this process depends on the activity of non-muscle myosin II (NMII), a family of actin-binding motor-proteins that participate in the formation of the cleavage furrow. The relevance of NMII for meiotic cell division, however, is poorly understood. The NMII family consists of three members, NMIIA, NMIIB, and NMIIC, containing different myosin heavy chains (MYH9, MYH10, and MYH14, respectively). We find that a single non-muscle myosin II, NMIIB, is required for meiotic cytokinesis in male but not female mice. Specifically, NMIIB-deficient spermatocytes exhibit cytokinetic failure in meiosis I, resulting in bi-nucleated secondary spermatocytes. Additionally, cytokinetic failure at meiosis II gives rise to bi-nucleated or even tetra-nucleated spermatids. These multi-nucleated spermatids fail to undergo normal differentiation, leading to male infertility. In spite of the presence of multiple non-muscle myosin II isoforms, we demonstrate that a single member, NMIIB, plays an essential and non-redundant role in cytokinesis during meiotic cell divisions of the male germline.
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Affiliation(s)
- Fang Yang
- Center for Animal Transgenesis and Germ Cell Research, Department of Animal Biology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, 19104, USA
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31
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Liu XJ. Polar body emission. Cytoskeleton (Hoboken) 2012; 69:670-85. [PMID: 22730245 DOI: 10.1002/cm.21041] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 05/15/2012] [Accepted: 05/21/2012] [Indexed: 12/13/2022]
Abstract
Generation of a haploid female germ cell, the egg, consists of two rounds of asymmetric cell division (meiosis I and meiosis II), yielding two diminutive and nonviable polar bodies and a large haploid egg. Animal eggs are also unique in the lack of centrioles and therefore form meiotic spindles without the pre-existence of the two dominant microtubule organizing centers (centrosomes) found in mitosis. Meiotic spindle assembly is further complicated by the unique requirement of sister chromatid mono-oriented in meiosis I. Nonetheless, the eggs appear to adopt many of the same proteins and mechanisms described in mitosis, with necessary modifications to accommodate their special needs. Unraveling these special modifications will not only help understanding animal reproduction, but should also enhance our understanding of cell division in general.
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Affiliation(s)
- X Johné Liu
- Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa Hospital Civic Campus, 1053 Carling Avenue, Ottawa, K1Y 4E9, Canada.
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32
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Spindle positioning in mammalian oocytes. Exp Cell Res 2012; 318:1442-7. [PMID: 22406266 DOI: 10.1016/j.yexcr.2012.02.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/21/2012] [Accepted: 02/22/2012] [Indexed: 11/22/2022]
Abstract
To preserve the maternal stores accumulated during oogenesis for further embryo development, oocytes divide asymmetrically which minimizes the volume of cytoplasm lost with each set of haploid genome. To ensure asymmetric division to occur, oocytes have to position their division spindle asymmetrically as well as tailor the size of daughter cells to the chromatin mass. In this review, we will discuss the recent advances in the field, with emphasis on the control mechanisms involved in meiotic spindle positioning in mammalian oocytes.
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33
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Kloc M, Ghobrial RM, Borsuk E, Kubiak JZ. Polarity and asymmetry during mouse oogenesis and oocyte maturation. Results Probl Cell Differ 2012; 55:23-44. [PMID: 22918799 DOI: 10.1007/978-3-642-30406-4_2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell polarity and asymmetry play a fundamental role in embryo development. The unequal segregation of determinants, cues, and activities is the major event in the differentiation of cell fate and function in all multicellular organisms. In oocytes, polarity and asymmetry in the distribution of different molecules are prerequisites for the progression and proper outcome of embryonic development. The mouse oocyte, like the oocytes of other mammals, seems to apply a less stringent strategy of polarization than other vertebrates. The mouse embryo undergoes a regulative type of development, which permits the full rectification of development even if the embryo loses up to half of its cells or its size is experimentally doubled during the early stages of embryogenesis. Such pliability is strongly related to the proper oocyte polarization before fertilization. Thus, the molecular mechanisms leading to the development and maintenance of oocyte polarity must be included in any fundamental understanding of the principles of embryo development. In this chapter, we provide an overview of current knowledge regarding the development and maintenance of polarity and asymmetry in the distribution of organelles and molecules in the mouse oocyte. Curiously, the mouse oocyte becomes polarized at least twice during ontogenesis; the question of how this phenomenon is achieved and what role it might play is addressed in this chapter.
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Affiliation(s)
- Malgorzata Kloc
- The Methodist Hospital, Department of Surgery, Houston, TX, USA.
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Sandquist JC, Kita AM, Bement WM. And the dead shall rise: actin and myosin return to the spindle. Dev Cell 2011; 21:410-9. [PMID: 21920311 DOI: 10.1016/j.devcel.2011.07.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 07/27/2011] [Accepted: 07/29/2011] [Indexed: 10/17/2022]
Abstract
The spindle directs chromosome partitioning in eukaryotes and, for the last three decades, has been considered primarily a structure based on microtubules, microtubule motors, and other microtubule binding proteins. However, a surprisingly large body of both old and new studies suggests roles for actin filaments (F-actin) and myosins (F-actin-based motor proteins) in spindle assembly and function. Here we review these data and conclude that in several cases the evidence for the participation of F-actin and myosins in spindle function is very strong, and in the situations where it is less strong, there is nevertheless enough evidence to warrant further investigation.
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Affiliation(s)
- Joshua C Sandquist
- Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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35
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Evans JP, Robinson DN. The spatial and mechanical challenges of female meiosis. Mol Reprod Dev 2011; 78:769-77. [PMID: 21774026 PMCID: PMC3196790 DOI: 10.1002/mrd.21358] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Accepted: 06/15/2011] [Indexed: 12/31/2022]
Abstract
Recent work shows that cytokinesis and other cellular morphogenesis events are tuned by an interplay among biochemical signals, cell shape, and cellular mechanics. In cytokinesis, this includes cross-talk between the cortical cytoskeleton and the mitotic spindle in coordination with cell cycle control, resulting in characteristic changes in cellular morphology and mechanics through metaphase and cytokinesis. The changes in cellular mechanics affect not just overall cell shape, but also mitotic spindle morphology and function. This review will address how these principles apply to oocytes undergoing the asymmetric cell divisions of meiosis I and II. The biochemical signals that regulate cell cycle timing during meiotic maturation and egg activation are crucial for temporal control of meiosis. Spatial control of the meiotic divisions is also important, ensuring that the chromosomes are segregated evenly and that meiotic division is clearly asymmetric, yielding two daughter cells - oocyte and polar body - with enormous volume differences. In contrast to mitotic cells, the oocyte does not undergo overt changes in cell shape with its progression through meiosis, but instead maintains a relatively round morphology with the exception of very localized changes at the time of polar body emission. Placement of the metaphase-I and -II spindles at the oocyte periphery is clearly important for normal polar body emission, although this is likely not the only control element. Here, consideration is given to how cellular mechanics could contribute to successful mammalian female meiosis, ultimately affecting egg quality and competence to form a healthy embryo.
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Affiliation(s)
- Janice P Evans
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA.
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36
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Wang Q, Racowsky C, Deng M. Mechanism of the chromosome-induced polar body extrusion in mouse eggs. Cell Div 2011; 6:17. [PMID: 21867530 PMCID: PMC3179692 DOI: 10.1186/1747-1028-6-17] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 08/25/2011] [Indexed: 12/11/2022] Open
Abstract
Background An oocyte undergoes two rounds of asymmetric division to generate a haploid gamete and two small polar bodies designed for apoptosis. Chromosomes play important roles in specifying the asymmetric meiotic divisions in the oocytes but the underlying mechanism is poorly understood. Results Chromosomes independently induce spindle formation and cortical actomyosin assembly into special cap and ring structures in the cortex of the oocyte. The spindle and the cortical cap/ring interact to generate mechanical forces, leading to polar body extrusion. Two distinct force-driven membrane changes were observed during 2nd polar body extrusion: a protrusion of the cortical cap and a membrane invagination induced by an anaphase spindle midzone. The cortical cap protrusion and invagination help rotate the spindle perpendicularly so that the spindle midzone can induce bilateral furrows at the shoulder of the protruding cap, leading to an abscission of the polar body. It is interesting to note that while the mitotic spindle midzone induces bilateral furrowing, leading to efficient symmetric division in the zygote, the meiotic spindle midzone induced cytokinetic furrowing only locally. Conclusions Distinct forces driving cortical cap protrusion and membrane invagination are involved in spindle rotation and polar body extrusion during meiosis II in mouse oocytes.
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Affiliation(s)
- Qiong Wang
- Department of Obstetrics and Gynecology and Reproductive Biology, 75 Francis Street, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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37
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Rhythmic actomyosin-driven contractions induced by sperm entry predict mammalian embryo viability. Nat Commun 2011; 2:417. [PMID: 21829179 PMCID: PMC3265380 DOI: 10.1038/ncomms1424] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 06/07/2011] [Indexed: 11/22/2022] Open
Abstract
Fertilization-induced cytoplasmic flows are a conserved feature of eggs in many species. However, until now the importance of cytoplasmic flows for the development of mammalian embryos has been unknown. Here, by combining a rapid imaging of the freshly fertilized mouse egg with advanced image analysis based on particle image velocimetry, we show that fertilization induces rhythmical cytoplasmic movements that coincide with pulsations of the protrusion forming above the sperm head. We find that these movements are caused by contractions of the actomyosin cytoskeleton triggered by Ca2+ oscillations induced by fertilization. Most importantly, the relationship between the movements and the events of egg activation makes it possible to use the movements alone to predict developmental potential of the zygote. In conclusion, this method offers, thus far, the earliest and fastest, non-invasive way to predict the viability of eggs fertilized in vitro and therefore can potentially improve greatly the prospects for IVF treatment. Cytoplasmic flows—the movement of cytoplasmic material—can be detected following the fertilization of an egg by a sperm in many species. In this study, rhythmic cytoplasmic flows are shown to be induced in mice by calcium-induced cytoskeleton contractions which could be used to predict the successful outcome of fertilization.
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38
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Brockmann C, Huarte J, Dugina V, Challet L, Rey E, Conne B, Swetloff A, Nef S, Chaponnier C, Vassalli JD. Beta- and gamma-cytoplasmic actins are required for meiosis in mouse oocytes. Biol Reprod 2011; 85:1025-39. [PMID: 21778137 DOI: 10.1095/biolreprod.111.091736] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
In mammals, female meiosis consists of two asymmetric cell divisions, which generate a large haploid oocyte and two small polar bodies. Asymmetric partitioning of the cytoplasm results from migration of the meiotic spindle toward the cortex and requires actin filaments. However, the subcellular localization and the role of the existing two cytoplasmic actin (CYA) isoforms, beta and gamma, have not been characterized. We show that beta- and gamma-CYA are differentially distributed in the maturing oocyte from late metaphase I as well as in preimplantation embryos. Gamma-CYA is preferentially enriched in oocyte cortices and is absent from all cell-cell contact areas from metaphase II until the blastocyst stage. Beta-CYA is enriched in contractile structures, at cytokinesis, at cell-cell contacts, and around the forming blastocoel. Alteration of beta- or gamma-CYA function by isoform-specific antibody microinjection suggests that gamma-CYA holds a major and specific role in the establishment and/or maintenance of asymmetry in meiosis I and in the maintenance of overall cortical integrity. In contrast, beta- and gamma-CYA, together, appear to participate in the formation and the cortical anchorage of the second meiotic spindle in waiting for fertilization. Finally, differences in gamma-CYA expression are amongst the earliest markers of cell fate determination in development.
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Affiliation(s)
- Céline Brockmann
- Departments of Genetic Medicine and Development and Pathology and Immunology, University of Geneva Medical School, Geneva, Switzerland
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39
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Buschiazzo J, Alonso TS, Biscoglio M, Antollini SS, Bonini IC. Nongenomic steroid- and ceramide-induced maturation in amphibian oocytes involves functional caveolae-like microdomains associated with a cytoskeletal environment. Biol Reprod 2011; 85:808-22. [PMID: 21653896 DOI: 10.1095/biolreprod.110.090365] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Stimulation of full-grown amphibian oocytes with progesterone initiates a nontranscriptional signaling pathway that converges in the activation of Cdc2/cyclin B and reentry into meiosis. We observed that cholesterol depletion mediated by methyl-beta-cyclodextrin (MbetaCD) inhibited meiotic maturation, suggesting involvement of membrane rafts. In the present study, we further characterized caveolae-like membranes from Rhinella arenarum oocytes biochemically and functionally. The identification by mass spectrometry of a nonmuscle myosin heavy-chain associated with caveolar membranes showed evidence of direct involvement of the underlying cytoskeletal environment in the structure of oocyte rafts. Biophysical analysis using the fluorescent probe Laurdan revealed that MbetaCD-mediated cholesterol depletion affected membrane lipid order. In line with this finding, cholesterol removal also affected the localization of the raft marker lipid GM1. Results demonstrated that ceramide is an effective inducer of maturation that alters the distribution of the raft markers caveolin-1, SRC, and GM1, while progesterone seems not to affect membrane microdomain integrity. Cholesterol depletion had a greater effect on ceramide-induced maturation, thus suggesting that ceramide is an inducer more vulnerable to changes in the plasma membrane. MbetaCD treatment delayed tyrosine phosphorylation and MAPK activation in progesterone-induced maturation. Functional studies regarding tyrosine phosphorylation raise the possibility that the hormone receptor is located in the nonraft membrane in the absence of ligand and that it translocates to the caveola when it binds to progesterone. The presence of raft markers and the finding of signaling molecules from MAPK cascade functionally associated to oocyte light membranes suggest that this caveolae-rich fraction efficiently recreates, in part, maturation signaling.
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Affiliation(s)
- Jorgelina Buschiazzo
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas, Bahía Blanca, Argentina
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40
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Pfender S, Kuznetsov V, Pleiser S, Kerkhoff E, Schuh M. Spire-type actin nucleators cooperate with Formin-2 to drive asymmetric oocyte division. Curr Biol 2011; 21:955-60. [PMID: 21620703 PMCID: PMC3128265 DOI: 10.1016/j.cub.2011.04.029] [Citation(s) in RCA: 181] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 03/30/2011] [Accepted: 04/18/2011] [Indexed: 12/24/2022]
Abstract
Oocytes mature into eggs by extruding half of their chromosomes in a small cell termed the polar body. Asymmetric oocyte division is essential for fertility [1], but despite its importance, little is known about its mechanism. In mammals, the meiotic spindle initially forms close to the center of the oocyte. Thus, two steps are required for asymmetric meiotic division: first, asymmetric spindle positioning and second, polar body extrusion. Here, we identify Spire1 and Spire2 as new key factors in asymmetric division of mouse oocytes. Spire proteins are novel types of actin nucleators that drive nucleation of actin filaments with their four WH2 actin-binding domains [2–6]. We show that Spire1 and Spire2 first mediate asymmetric spindle positioning by assembling an actin network that serves as a substrate for spindle movement. Second, they drive polar body extrusion by promoting assembly of the cleavage furrow. Our data suggest that Spire1 and Spire2 cooperate with Formin-2 (Fmn2) to nucleate actin filaments in mouse oocytes and that both types of nucleators act as a functional unit. This study not only reveals how Spire1 and Spire2 drive two critical steps of asymmetric oocyte division, but it also uncovers the first physiological function of Spire-type actin nucleators in vertebrates.
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Affiliation(s)
- Sybille Pfender
- Medical Research Council, Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
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41
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Heissler SM, Manstein DJ. Comparative kinetic and functional characterization of the motor domains of human nonmuscle myosin-2C isoforms. J Biol Chem 2011; 286:21191-202. [PMID: 21478157 PMCID: PMC3122181 DOI: 10.1074/jbc.m110.212290] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Nonmuscle myosins are widely distributed and play important roles in the maintenance of cell morphology and cytokinesis. In this study, we compare the detailed kinetic and functional characterization of naturally occurring transcript variants of the motor domain of human nonmuscle myosin heavy chain (NMHC)-2C. NMHC-2C is alternatively spliced both in loop-1 and loop-2. Isoform 2C0 contains no inserts in either of the loops and represents the shortest isoform. An 8-amino acid extension in the loop-1 region is present in isoforms 2C1 and 2C1C2. Isoform 2C1C2 additionally displays a 33-amino acid extension in the loop-2 region. Transient kinetic experiments indicate increased rate constants for F-actin binding by isoform 2C1C2 in the absence and presence of nucleotide, which can be attributed to the loop-2 extension. ADP binding shows only minor differences for the three transcript variants. In contrast, larger differences are observed for the rates of ADP release both in the absence and presence of F-actin. The largest differences are observed between isoforms 2C0 and 2C1C2. In the absence and presence of F-actin, isoform 2C1C2 displays a 5–7-fold increase in ADP affinity. Moreover, our results indicate that the ADP release kinetics of all three isoforms are modulated by changes in the concentration of free Mg2+ ions. The greatest responsiveness of the NMHC-2C isoforms is observed in the physiological range from 0.2 to 1.5 mm free Mg2+ ions, affecting their duty ratio, velocity, and tension-bearing properties.
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Affiliation(s)
- Sarah M Heissler
- Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
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42
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Ca2+ signaling during mammalian fertilization: requirements, players, and adaptations. Cold Spring Harb Perspect Biol 2011; 3:cshperspect.a006767. [PMID: 21441584 DOI: 10.1101/cshperspect.a006767] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Changes in the intracellular concentration of calcium ([Ca(2+)](i)) represent a vital signaling mechanism enabling communication among cells and between cells and the environment. The initiation of embryo development depends on a [Ca(2+)](i) increase(s) in the egg, which is generally induced during fertilization. The [Ca(2+)](i) increase signals egg activation, which is the first stage in embryo development, and that consist of biochemical and structural changes that transform eggs into zygotes. The spatiotemporal patterns of [Ca(2+)](i) at fertilization show variability, most likely reflecting adaptations to fertilizing conditions and to the duration of embryonic cell cycles. In mammals, the focus of this review, the fertilization [Ca(2+)](i) signal displays unique properties in that it is initiated after gamete fusion by release of a sperm-derived factor and by periodic and extended [Ca(2+)](i) responses. Here, we will discuss the events of egg activation regulated by increases in [Ca(2+)](i), the possible downstream targets that effect these egg activation events, and the property and identity of molecules both in sperm and eggs that underpin the initiation and persistence of the [Ca(2+)](i) responses in these species.
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43
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Larson SM, Lee HJ, Hung PH, Matthews LM, Robinson DN, Evans JP. Cortical mechanics and meiosis II completion in mammalian oocytes are mediated by myosin-II and Ezrin-Radixin-Moesin (ERM) proteins. Mol Biol Cell 2010; 21:3182-92. [PMID: 20660156 PMCID: PMC2938384 DOI: 10.1091/mbc.e10-01-0066] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 07/01/2010] [Accepted: 07/12/2010] [Indexed: 11/11/2022] Open
Abstract
Cell division is inherently mechanical, with cell mechanics being a critical determinant governing the cell shape changes that accompany progression through the cell cycle. The mechanical properties of symmetrically dividing mitotic cells have been well characterized, whereas the contribution of cellular mechanics to the strikingly asymmetric divisions of female meiosis is very poorly understood. Progression of the mammalian oocyte through meiosis involves remodeling of the cortex and proper orientation of the meiotic spindle, and thus we hypothesized that cortical tension and stiffness would change through meiotic maturation and fertilization to facilitate and/or direct cellular remodeling. This work shows that tension in mouse oocytes drops about sixfold during meiotic maturation from prophase I to metaphase II and then increases ∼1.6-fold upon fertilization. The metaphase II egg is polarized, with tension differing ∼2.5-fold between the cortex over the meiotic spindle and the opposite cortex, suggesting that meiotic maturation is accompanied by assembly of a cortical domain with stiffer mechanics as part of the process to achieve asymmetric cytokinesis. We further demonstrate that actin, myosin-II, and the ERM (Ezrin/Radixin/Moesin) family of proteins are enriched in complementary cortical domains and mediate cellular mechanics in mammalian eggs. Manipulation of actin, myosin-II, and ERM function alters tension levels and also is associated with dramatic spindle abnormalities with completion of meiosis II after fertilization. Thus, myosin-II and ERM proteins modulate mechanical properties in oocytes, contributing to cell polarity and to completion of meiosis.
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Affiliation(s)
- Stephanie M. Larson
- *Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, and
| | - Hyo J. Lee
- *Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, and
| | - Pei-hsuan Hung
- *Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, and
| | - Lauren M. Matthews
- *Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, and
| | - Douglas N. Robinson
- Department of Cell Biology, and
- Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD 21205
| | - Janice P. Evans
- *Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, and
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44
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Brunet S, Verlhac MH. Positioning to get out of meiosis: the asymmetry of division. Hum Reprod Update 2010; 17:68-75. [DOI: 10.1093/humupd/dmq044] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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45
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Simerly CR, Castro CA, Jacoby E, Grund K, Turpin J, McFarland D, Champagne J, Jimenez JB, Frost P, Bauer C, Hewitson L, Schatten G. Assisted Reproductive Technologies (ART) with baboons generate live offspring: a nonhuman primate model for ART and reproductive sciences. Reprod Sci 2010; 17:917-30. [PMID: 20631291 DOI: 10.1177/1933719110374114] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Human reproduction has benefited significantly by investigating nonhuman primate (NHP) models, especially rhesus macaques. To expand the Old World monkey species available for human reproductive studies, we present protocols in baboons, our closest Old World primate relatives, for assisted reproductive technologies (ART) leading to live born offspring. Baboons complement rhesus by confirming or modifying observations generated in humans often obtained by the study of clinically discarded specimens donated by anonymous infertility patient couples. Here, baboon ART protocols, including oocyte collection, in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), preimplantation development to blastocyst stage, and embryo transfer techniques are described. With baboon ART methodologies in place, motility during baboon fertilization was investigated by time-lapse video microscopy (TLVM). The first ART baboons produced by ICSI, a pair of male twins, were delivered naturally at 165 days postgestation. Genetic testing of these twins confirmed their ART parental origins and demonstrated that they are unrelated fraternal twins not identicals. These results have implications for ART outcomes, embryonic stem cell (ESC) derivation, and reproductive sciences.
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Affiliation(s)
- Calvin R Simerly
- Division of Developmental and Regenerative Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, Pittsburgh Development Center; Magee-Womens Research Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA
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46
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Cai L, Fritz D, Stefanovic L, Stefanovic B. Nonmuscle myosin-dependent synthesis of type I collagen. J Mol Biol 2010; 401:564-78. [PMID: 20603131 DOI: 10.1016/j.jmb.2010.06.057] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 06/09/2010] [Accepted: 06/25/2010] [Indexed: 01/15/2023]
Abstract
Type I collagen, synthesized in all tissues as the heterotrimer of two alpha1(I) polypeptides and one alpha2(I) polypeptide, is the most abundant protein in the human body. Here we show that intact nonmuscle myosin filaments are required for the synthesis of heterotrimeric type I collagen. Conserved 5' stem-loop in collagen alpha1(I) and alpha2(I) mRNAs binds the RNA-binding protein LARP6. LARP6 interacts with nonmuscle myosin through its C-terminal domain and associates collagen mRNAs with the filaments. Dissociation of nonmuscle myosin filaments results in secretion of collagen alpha1(I) homotrimer, diminished intracellular colocalization of collagen alpha1(I) and alpha2(I) polypeptides (required for folding of the heterotrimer), and their increased intracellular degradation. Inhibition of the motor function of myosin has similar collagen-specific effects, while disruption of actin filaments has a general effect on protein secretion. Nonmuscle myosin copurifies with polysomes, and there is a subset of polysomes involved in myosin-dependent translation of collagen mRNAs. These results indicate that association of collagen mRNAs with nonmuscle myosin filaments is necessary to coordinately synthesize collagen alpha1(I) and alpha2(I) polypeptides. We postulate that LARP6/myosin-dependent mechanism regulates the synthesis of heterotrimeric type I collagen by coordinating the translation of collagen mRNAs.
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Affiliation(s)
- Le Cai
- Department of Biomedical Sciences, College of Medicine, Florida State University, 1115 West Call Street, Tallahassee, FL 32306, USA
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47
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Deng M, Li R. Sperm chromatin-induced ectopic polar body extrusion in mouse eggs after ICSI and delayed egg activation. PLoS One 2009; 4:e7171. [PMID: 19787051 PMCID: PMC2746308 DOI: 10.1371/journal.pone.0007171] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 08/26/2009] [Indexed: 12/05/2022] Open
Abstract
Meiotic chromosomes in an oocyte are not only a maternal genome carrier but also provide a positional signal to induce cortical polarization and define asymmetric meiotic division of the oocyte, resulting in polar body extrusion and haploidization of the maternal genome. The meiotic chromosomes play dual function in determination of meiosis: 1) organizing a bipolar spindle formation and 2) inducing cortical polarization and assembly of a distinct cortical cytoskeleton structure in the overlying cortex for polar body extrusion. At fertilization, a sperm brings exogenous paternal chromatin into the egg, which induces ectopic cortical polarization at the sperm entry site and leads to a cone formation, known as fertilization cone. Here we show that the sperm chromatin-induced fertilization cone formation is an abortive polar body extrusion due to lack of spindle induction by the sperm chromatin during fertilization. If experimentally manipulating the fertilization process to allow sperm chromatin to induce both cortical polarization and spindle formation, the fertilization cone can be converted into polar body extrusion. This suggests that sperm chromatin is also able to induce polar body extrusion, like its maternal counterpart. The usually observed cone formation instead of ectopic polar body extrusion induced by sperm chromatin during fertilization is due to special sperm chromatin compaction which restrains it from rapid spindle induction and therefore provides a protective mechanism to prevent a possible paternal genome loss during ectopic polar body extrusion.
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Affiliation(s)
- Manqi Deng
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- * E-mail: (MD); (RL)
| | - Rong Li
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- * E-mail: (MD); (RL)
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48
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Ostrakhovitch EA. Interplay between Numb and Notch in epithelial cancers: role for dual oxidase maturation factor. Eur J Cancer 2009; 45:2071-6. [PMID: 19523816 DOI: 10.1016/j.ejca.2009.05.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2009] [Accepted: 05/15/2009] [Indexed: 10/20/2022]
Abstract
Numb and Notch signalling pathways are vitally important in cell fate and differentiation. The outcome of these signalling processes is determined by a delicate balance between opposing effects of Notch and Numb. Imbalance in Numb/Notch regulation was implicated in aberrant differentiation programme and epithelial cancer progression and metastasis. Recent identification of Numb-interacting protein (NIP), which is also known as dual oxidase maturation factor, and was shown to associate with Numb and DUOX and promote their translocation, sheds a new light on how Numb/Notch network may be coordinated in epithelial cancers. Here, a possible link between Numb, Notch and Dual oxidase maturation factor is examined.
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Affiliation(s)
- E A Ostrakhovitch
- Department of Chemistry, University of Western Ontario, London, Ontario, Canada.
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Azoury J, Lee KW, Georget V, Rassinier P, Leader B, Verlhac MH. Spindle positioning in mouse oocytes relies on a dynamic meshwork of actin filaments. Curr Biol 2008; 18:1514-9. [PMID: 18848445 DOI: 10.1016/j.cub.2008.08.044] [Citation(s) in RCA: 225] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 07/23/2008] [Accepted: 08/14/2008] [Indexed: 10/21/2022]
Abstract
Female meiosis in higher organisms consists of highly asymmetric divisions, which retain most maternal stores in the oocyte for embryo development. Asymmetric partitioning of the cytoplasm results from the spindle's "off-center" positioning, which, in mouse oocytes, depends mainly on actin filaments [1, 2]. This is a unique situation compared to most systems, in which spindle positioning requires interactions between astral microtubules and cortical actin filaments [3]. Formin 2, a straight-actin-filament nucleator, is required for the first meiotic spindle migration to the cortex and cytokinesis in mouse oocytes [4, 5]. Although the requirement for actin filaments in the control of spindle positioning is well established in this model, no one has been able to detect them in the cytoplasm [6]. Through the expression of an F-actin-specific probe and live confocal microscopy, we show the presence of a cytoplasmic actin meshwork, organized by Formin 2, that controls spindle migration. In late meiosis I, these filaments organize into a spindle-like F-actin structure, which is connected to the cortex. At anaphase, global reorganization of this meshwork allows polar-body extrusion. In addition, using actin-YFP, our FRAP analysis confirms the presence of a highly dynamic cytoplasmic actin meshwork that is tightly regulated in time and space.
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Affiliation(s)
- Jessica Azoury
- Unité Mixte de Recherche 7622, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Paris, France
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Schuh M, Ellenberg J. A new model for asymmetric spindle positioning in mouse oocytes. Curr Biol 2008; 18:1986-92. [PMID: 19062278 DOI: 10.1016/j.cub.2008.11.022] [Citation(s) in RCA: 229] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 10/29/2008] [Accepted: 11/12/2008] [Indexed: 10/21/2022]
Abstract
An oocyte matures into an egg by extruding half of the chromosomes in a small polar body. This extremely asymmetric division enables the oocyte to retain sufficient storage material for the development of the embryo after fertilization. To divide asymmetrically, mammalian oocytes relocate the spindle from their center to the cortex. In all mammalian species analyzed so far, including human, mouse, cow, pig, and hamster, spindle relocation depends on filamentous actin (F-actin). However, even though spindle relocation is essential for fertility, the involved F-actin structures and the mechanism by which they relocate the spindle are unknown. Here we show in live mouse oocytes that spindle relocation requires a continuously reorganizing cytoplasmic actin network nucleated by Formin-2 (Fmn2). We found that the spindle poles were enriched in activated myosin and pulled on this network. Inhibition of myosin activation by myosin light chain kinase (MLCK) stopped pulling and spindle relocation, indicating that myosin pulling creates the force that drives spindle movement. Based on these results, we propose the first mechanistic model for asymmetric spindle positioning in mammalian oocytes and validate five of its key predictions experimentally.
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Affiliation(s)
- Melina Schuh
- European Molecular Biology Laboratory (EMBL), Gene Expression Unit, Heidelberg, Germany
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