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Wang H, Kinsey WH. Signaling Proteins Recruited to the Sperm Binding Site: Role of β-Catenin and Rho A. Front Cell Dev Biol 2022; 10:886664. [PMID: 35646891 PMCID: PMC9136404 DOI: 10.3389/fcell.2022.886664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 03/29/2022] [Indexed: 01/19/2023] Open
Abstract
Sperm interaction with the oocyte plasma membrane triggers a localized response in the mouse oocyte that leads to remodeling of oocyte surface as well as the underlying cortical actin layer. The recent demonstration that PTK2B is recruited and activated at the sperm binding site raised the possibility that multiple signaling events may be activated during this stage of fertilization. The present study demonstrated that β-catenin and Rho A were recruited to the cortex underlying bound/fused sperm. To determine whether sperm-oocyte contact was sufficient to initiate β-catenin recruitment, Cd9-null, and PTK2b-null oocytes were tested for the ability to recruit β-catenin to sperm binding sites. Both Cd9 and Ptk2b ablation reduced β-catenin recruitment raising the possibility that PTK2B may act downstream of CD9 in the response to sperm binding/fusion. Further immunofluorescence study revealed that β-catenin co-localized with f-actin in the interstitial regions between actin layer fenestrae. Rho A, in contrast, was arranged underneath the actin layer in both the fenestra and the interstitial regions suggesting that they may play different roles in the oocyte.
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2
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Epithelial and Neural Cadherin in Mammalian Fertilization: Studies in the Mouse Model. Cells 2021; 11:cells11010102. [PMID: 35011663 PMCID: PMC8750299 DOI: 10.3390/cells11010102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/20/2021] [Accepted: 12/24/2021] [Indexed: 12/18/2022] Open
Abstract
Successful mammalian fertilization requires a well-orchestrated sequence of molecular events leading to gamete fusion. Since this interaction involves Ca2+-dependent adhesion events, the participation of the Ca+2-dependent cell-cell adhesion proteins Epithelial (E-cad) and Neural (N-cad) cadherin is envisaged. We have previously reported the expression of E-cad and N-cad in human gametes and showed evidence of their involvement in sperm-oocyte adhesion events leading to fertilization. To overcome ethical limitations associated with the use of human gametes in fertilization-related studies, the mouse has been selected worldwide as the experimental model for over 4 decades. Herein, we report a detailed study aimed at characterizing the expression of E-cad and N-cad in murine gametes and their involvement in murine fertilization using specific antibodies and blocking peptides towards both adhesion proteins. E-cad and N-cad protein forms, as well as other members of the adhesion complex, specifically β-catenin and actin, were identified in spermatozoa, cumulus cells and oocytes protein extracts by means of Western immunoblotting. In addition, subcellular localization of these proteins was determined in whole cells using optical fluorescent microscopy. Gamete pre-incubation with anti-E-cad (ECCD-1) or N-cad (H-63) antibodies resulted in decreased (p < 0.05) In Vitro Fertilization (IVF) rates, when using both cumulus-oocytes complexes and cumulus-free oocytes. Moreover, IVF assays done with denuded oocytes and either antibodies or blocking peptides against E-cad and N-cad led to lower (p < 0.05) fertilization rates. When assessing each step, penetration of the cumulus mass was lower (p < 0.05) when spermatozoa were pre-incubated with ECCD-1 or blocking peptides towards E-cad or towards both E- and N-cad. Moreover, sperm-oolemma binding was impaired (p < 0.0005) after sperm pre-incubation with E-cad antibody or blocking peptide towards E-cad, N-cad or both proteins. Finally, sperm-oocyte fusion was lower (p < 0.05) after sperm pre-incubation with either antibody or blocking peptide against E-cad or N-cad. Our studies demonstrate the expression of members of the adherent complex in the murine model, and the use of antibodies and specific peptides revealed E-cad and N-cad participation in mammalian fertilization.
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Abstract
Fertilization is a multistep process that culminates in the fusion of sperm and egg, thus marking the beginning of a new organism in sexually reproducing species. Despite its importance for reproduction, the molecular mechanisms that regulate this singular event, particularly sperm-egg fusion, have remained mysterious for many decades. Here, we summarize our current molecular understanding of sperm-egg interaction, focusing mainly on mammalian fertilization. Given the fundamental importance of sperm-egg fusion yet the lack of knowledge of this process in vertebrates, we discuss hallmarks and emerging themes of cell fusion by drawing from well-studied examples such as viral entry, placenta formation, and muscle development. We conclude by identifying open questions and exciting avenues for future studies in gamete fusion. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Victoria E Deneke
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria; ,
| | - Andrea Pauli
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria; ,
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Wang H, Hong X, Kinsey WH. Sperm-oocyte signaling: the role of IZUMO1R and CD9 in PTK2B activation and actin remodeling at the sperm binding site†. Biol Reprod 2021; 104:1292-1301. [PMID: 33724343 PMCID: PMC8182024 DOI: 10.1093/biolre/ioab048] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 02/09/2021] [Accepted: 03/15/2021] [Indexed: 01/19/2023] Open
Abstract
Sperm-oocyte binding initiates an outside-in signaling event in the mouse oocyte that triggers recruitment and activation of the cytosolic protein kinase PTK2B in the cortex underlying the bound sperm. While not involved in gamete fusion, PTK2B activity promotes actin remodeling events important during sperm incorporation. However, the mechanism by which sperm-oocyte binding activates PTK2B is unknown, and the present study examined the possibility that sperm interaction with specific oocyte surface proteins plays an important role in PTK2B activation. Imaging studies revealed that as IZUMO1R and CD9 became concentrated at the sperm binding site, activated (phosphorylated) PTK2B accumulated in the cortex underlying the sperm head and in microvilli partially encircling the sperm head. In order to determine whether IZUMO1R and/or CD9 played a significant role in PTK2B recruitment and activation at the sperm binding site, the ability of oocytes null for Izumo1r or Cd9, to initiate an increase in PTK2B content and activation was tested. The results revealed that IZUMO1R played a minor role in PTK2B activation and had no effect on actin remodeling; however, CD9 played a very significant role in PTK2B activation and subsequent actin remodeling at the sperm binding site. These findings suggest the possibility that interaction of sperm surface proteins with CD9 or CD9-associated oocyte proteins triggers PTK2B activation at the sperm binding site.
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Affiliation(s)
- Huizhen Wang
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, KS, USA
| | - Xiaoman Hong
- Department of Molecular and Integrative Physiology, University of Kansas School of Medicine, Kansas City, KS, USA
| | - William H Kinsey
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, KS, USA,Correspondence: Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, KS 66160, USA. E-mail:
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Ramírez‐Ramírez D, Salgado‐Lucio ML, Roa‐Espitia AL, Fierro R, González‐Márquez H, Cordero‐Martínez J, Hernández‐González EO. Rac1 is necessary for capacitation and acrosome reaction in guinea pig spermatozoa. J Cell Biochem 2019; 121:2864-2876. [DOI: 10.1002/jcb.29521] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 10/10/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Danelia Ramírez‐Ramírez
- Doctorado en Ciencias Biológicas y de la SaludUniversidad Autónoma Metropolitana‐Iztapalapa Ciudad de México México
| | - Monica L. Salgado‐Lucio
- Departamento de Biología CelularCentro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional México City México
| | - Ana L. Roa‐Espitia
- Departamento de Biología CelularCentro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional México City México
| | - Reyna Fierro
- Departamento de Ciencias de la SaludUniversidad Autónoma Metropolitana‐Iztapalapa Ciudad de México México
| | - Humberto González‐Márquez
- Departamento de Ciencias de la SaludUniversidad Autónoma Metropolitana‐Iztapalapa Ciudad de México México
| | - Joaquín Cordero‐Martínez
- Departamento de Bioquímica, Escuela Nacional de Ciencias BiológicasInstituto Politécnico Nacional Ciudad de México México
| | - Enrique O. Hernández‐González
- Departamento de Biología CelularCentro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional México City México
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Matsu-Ura T, Shirakawa H, Suzuki KGN, Miyamoto A, Sugiura K, Michikawa T, Kusumi A, Mikoshiba K. Dual-FRET imaging of IP 3 and Ca 2+ revealed Ca 2+-induced IP 3 production maintains long lasting Ca 2+ oscillations in fertilized mouse eggs. Sci Rep 2019; 9:4829. [PMID: 30886280 PMCID: PMC6423007 DOI: 10.1038/s41598-019-40931-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 02/19/2019] [Indexed: 01/31/2023] Open
Abstract
In most species, fertilization induces Ca2+ transients in the egg. In mammals, the Ca2+ rises are triggered by phospholipase Cζ (PLCζ) released from the sperm; IP3 generated by PLCζ induces Ca2+ release from the intracellular Ca2+ store through IP3 receptor, termed IP3-induced Ca2+ release. Here, we developed new fluorescent IP3 sensors (IRIS-2s) with the wider dynamic range and higher sensitivity (Kd = 0.047-1.7 μM) than that we developed previously. IRIS-2s employed green fluorescent protein and Halo-protein conjugated with the tetramethylrhodamine ligand as fluorescence resonance energy transfer (FRET) donor and acceptor, respectively. For simultaneous imaging of Ca2+ and IP3, using IRIS-2s as the IP3 sensor, we developed a new single fluorophore Ca2+ sensor protein, DYC3.60. With IRIS-2s and DYC3.60, we found that, right after fertilization, IP3 concentration ([IP3]) starts to increase before the onset of the first Ca2+ wave. [IP3] stayed at the elevated level with small peaks followed after Ca2+ spikes through Ca2+ oscillations. We detected delays in the peak of [IP3] compared to the peak of each Ca2+ spike, suggesting that Ca2+-induced regenerative IP3 production through PLC produces small [IP3] rises to maintain [IP3] over the basal level, which results in long lasting Ca2+ oscillations in fertilized eggs.
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Affiliation(s)
- Toru Matsu-Ura
- Laboratory for Developmental Neurobiology, Center for Brain Sciences, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Hideki Shirakawa
- Department of Applied Physics and Chemistry, The University of Electro-Communications, Tokyo, 182-8585, Japan
| | - Kenichi G N Suzuki
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Akitoshi Miyamoto
- Laboratory for Developmental Neurobiology, Center for Brain Sciences, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.,Laboratory of Single-Molecule Cell Biology, Kyoto University Graduate School of Biostudies, Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Kotomi Sugiura
- Division of Mucosal Vaccines, International Research and Development Center for Mucosal Vaccine, The Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
| | - Takayuki Michikawa
- Laboratory for Biotechnological Optics Research, Center for Advanced Photonics, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Akihiro Kusumi
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, Center for Brain Sciences, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. .,Department of Pharmacology, Keio University School of Medicine, 35 Shinanomachi, Shnjukuku, Tokyo, 160-8582, Japan. .,Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, 201210, China.
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7
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Wang H, Luo J, Carlton C, McGinnis LK, Kinsey WH. Sperm-oocyte contact induces outside-in signaling via PYK2 activation. Dev Biol 2017; 428:52-62. [PMID: 28527703 PMCID: PMC5539980 DOI: 10.1016/j.ydbio.2017.05.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 05/15/2017] [Accepted: 05/17/2017] [Indexed: 01/20/2023]
Abstract
Fertilization is a multi-step process that begins with plasma membrane interactions that enable sperm - oocyte binding followed by fusion of the sperm and oocyte plasma membranes. Once membrane fusion has occurred, sperm incorporation involves actin remodeling events within the oocyte cortex that allow the sperm head to penetrate the cortical actin layer and gain access to the ooplasm. Despite the significance for reproduction, the control mechanisms involved in gamete binding, fusion, and sperm incorporation are poorly understood. While it is known that proline - rich tyrosine kinase 2 (PYK2 or PTK2b) kinase activity plays an important role in fertilization, its specific function has not been addressed. The present study made use of a zona-free mouse oocyte fertilization assay to investigate the relationship between PYK2 activity and sperm - oocyte binding and fusion, as well as localized changes in actin polymerization and sperm incorporation. In this assay, the majority of bound sperm had no apparent effect on the oocyte and only a few became incorporated into the ooplasm. However, a subset of bound sperm were associated with a localized response in which PYK2 was recruited to the oocyte cortex where it frequently co-localized with a ring or disk of f-actin. The frequency of sperm-oocyte binding sites that exhibited this actin response was reduced in pyk2-/- oocytes and the pyk2-/- oocytes proved less efficient at incorporating sperm, indicating that this protein kinase may have an important role in sperm incorporation. The response of PYK2 to sperm-oocyte interaction appeared unrelated to gamete fusion since PYK2 was recruited to sperm - binding sites under conditions where sperm - oocyte fusion was prevented and since PYK2 suppression or ablation did not prevent sperm - oocyte fusion. While a direct correlation between the PYK2 response in the oocyte and the successful incorporation of individual bound sperm remains to be established, these findings suggest a model in which the oocyte is not a passive participant in fertilization, but instead responds to sperm contact by localized PYK2 signaling that promotes actin remodeling events required to physically incorporate the sperm head into the ooplasm.
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Affiliation(s)
- Huizhen Wang
- Department of Anatomy & Cell Biology, Univ. of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Jinping Luo
- Department of Anatomy & Cell Biology, Univ. of Kansas Medical Center, Kansas City, KS 66160, USA; Applied StemCell Inc., Milpitas, CA 95035, USA
| | - Carol Carlton
- Department of Anatomy & Cell Biology, Univ. of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Lynda K McGinnis
- Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, University of Southern California, Los Angeles, CA 90033, USA
| | - William H Kinsey
- Department of Anatomy & Cell Biology, Univ. of Kansas Medical Center, Kansas City, KS 66160, USA.
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8
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Angeles-Floriano T, Roa-Espitia AL, Baltiérrez-Hoyos R, Cordero-Martínez J, Elizondo G, Hernández-González EO. Absence of aryl hydrocarbon receptor alters CDC42 expression and prevents actin polymerization during capacitation. Mol Reprod Dev 2016; 83:1015-1026. [DOI: 10.1002/mrd.22736] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/12/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Tania Angeles-Floriano
- Departamento de Biología Celular; CINVESTAV-IPN; Av. Instituto Politécnico Nacional 2508; CP 07360; México DF México
| | - Ana L. Roa-Espitia
- Departamento de Biología Celular; CINVESTAV-IPN; Av. Instituto Politécnico Nacional 2508; CP 07360; México DF México
| | - Rafael Baltiérrez-Hoyos
- Facultad de Medicina y Cirugía; Universidad Autónoma Benito Juárez de Oaxaca; Oaxaca; Cátedras CONACYT
| | - Joaquin Cordero-Martínez
- Departamento de Biología Celular; CINVESTAV-IPN; Av. Instituto Politécnico Nacional 2508; CP 07360; México DF México
| | - Guillermo Elizondo
- Departamento de Biología Celular; CINVESTAV-IPN; Av. Instituto Politécnico Nacional 2508; CP 07360; México DF México
| | - Enrique O. Hernández-González
- Departamento de Biología Celular; CINVESTAV-IPN; Av. Instituto Politécnico Nacional 2508; CP 07360; México DF México
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Ravaux B, Garroum N, Perez E, Willaime H, Gourier C. A specific flagellum beating mode for inducing fusion in mammalian fertilization and kinetics of sperm internalization. Sci Rep 2016; 6:31886. [PMID: 27539564 PMCID: PMC4990900 DOI: 10.1038/srep31886] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 07/26/2016] [Indexed: 12/30/2022] Open
Abstract
The salient phases of fertilization are gamete adhesion, membrane fusion, and internalization of the spermatozoon into the oocyte but the precise timeline and the molecular, membrane and cell mechanisms underlying these highly dynamical events are far from being established. The high motility of the spermatozoa and the unpredictable location of sperm/egg fusion dramatically hinder the use of real time imaging optical techniques that should directly provide the dynamics of cell events. Using an approach based on microfluidics technology, the sperm/egg interaction zone was imaged with the best front view, and the timeline of the fertilization events was established with an unparalleled temporal accuracy from the onset of gamete contact to full sperm DNA decondensation. It reveals that a key element of the adhesion phase to initiate fusion is the oscillatory motion of the sperm head on the oocyte plasma membrane generated by a specific flagellum-beating mode. It also shows that the incorporation of the spermatozoon head is a two steps process that includes simultaneous diving, tilt, and plasma membrane degradation of the sperm head into the oocyte and subsequent DNA decondensation.
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Affiliation(s)
- Benjamin Ravaux
- Laboratoire de Physique Statistique, Ecole Normale Superieure/PSL Research University, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France
| | - Nabil Garroum
- Laboratoire de Physique Statistique, Ecole Normale Superieure/PSL Research University, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France
| | - Eric Perez
- Laboratoire de Physique Statistique, Ecole Normale Superieure/PSL Research University, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France
| | - Hervé Willaime
- Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris (IRCP), F-75005 Paris, France
| | - Christine Gourier
- Laboratoire de Physique Statistique, Ecole Normale Superieure/PSL Research University, UPMC Univ Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France
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Lee JS, Kwon WS, Rahman MS, Yoon SJ, Park YJ, Pang MG. Actin-related protein 2/3 complex-based actin polymerization is critical for male fertility. Andrology 2015. [DOI: 10.1111/andr.12076] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- J.-S. Lee
- Department of Animal Science and Technology; Chung-Ang University; Anseong Korea
| | - W.-S. Kwon
- Department of Animal Science and Technology; Chung-Ang University; Anseong Korea
| | - M. S. Rahman
- Department of Animal Science and Technology; Chung-Ang University; Anseong Korea
| | - S.-J. Yoon
- Department of Animal Science and Technology; Chung-Ang University; Anseong Korea
| | - Y.-J. Park
- Department of Animal Science and Technology; Chung-Ang University; Anseong Korea
| | - M.-G. Pang
- Department of Animal Science and Technology; Chung-Ang University; Anseong Korea
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Lipinska AP, D’hondt S, Van Damme EJM, De Clerck O. Uncovering the genetic basis for early isogamete differentiation: a case study of Ectocarpus siliculosus. BMC Genomics 2013; 14:909. [PMID: 24359479 PMCID: PMC3879662 DOI: 10.1186/1471-2164-14-909] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 12/17/2013] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The phenomenon of sexual reproduction characterizes nearly all eukaryotes, with anisogamy being the most prevalent form of gamete discrimination. Since dimorphic gametes most likely descend from equal-sized specialized germ cells, identifying the genetic bases of the early functional diversification in isogametes can provide better understanding of the evolution of sexual dimorphism. However, despite the potential importance to the evolutionary biology field, no comprehensive survey of the transcriptome profiling in isomorphic gametes has been reported hitherto. RESULTS Gamete differentiation on the genomic level was investigated using Ectocarpus siliculosus, a model organism for brown algal lineage which displays an isogamous sexual reproduction cycle. Transcriptome libraries of male and female gametes were generated using Next Generation Sequencing technology (SOLiD) and analyzed to identify differentially regulated genes and pathways with potential roles in fertilization and gamete specialization. Gamete transcriptomes showed a high level of complexity with a large portion of gender specific gene expression. Our results indicate that over 4,000 of expressed genes are differentially regulated between male and female, including sequences related to cell movement, carbohydrate and lipid metabolism, signaling, transport and RNA processing. CONCLUSIONS This first comprehensive transcriptomic study of protist isogametes describes considerable adaptation to distinct sexual roles, suggesting that functional anisogamy precedes morphological differentiation. Several sex-biased genes and pathways with a putative role in reproduction were identified, providing the basis for more detailed investigations of the mechanisms underlying evolution of mating types and sexual dimorphism.
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Affiliation(s)
- Agnieszka P Lipinska
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Krijgslaan 281, Building S8, 9000 Ghent, Belgium
| | - Sofie D’hondt
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Krijgslaan 281, Building S8, 9000 Ghent, Belgium
| | - Els JM Van Damme
- Department of Molecular Biotechnology, Laboratory of Biochemistry and Glycobiology, Ghent University, Coupure Links 653, 9000 Gent, Belgium
| | - Olivier De Clerck
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Krijgslaan 281, Building S8, 9000 Ghent, Belgium
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Takahashi T, Kikuchi T, Kidokoro Y, Shirakawa H. Ca²⁺ influx-dependent refilling of intracellular Ca²⁺ stores determines the frequency of Ca²⁺ oscillations in fertilized mouse eggs. Biochem Biophys Res Commun 2012; 430:60-5. [PMID: 23159627 DOI: 10.1016/j.bbrc.2012.11.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 11/06/2012] [Indexed: 11/19/2022]
Abstract
On mammalian fertilization, long-lasting Ca(2+) oscillations are induced in the egg by the fusing spermatozoon. While each transient Ca(2+) increase in Ca(2+) concentration ([Ca(2+)]) in the cytosol is due to Ca(2+) release from the endoplasmic reticulum (ER), Ca(2+) influx from outside is required for Ca(2+) oscillations to persist. In this study, we investigated how Ca(2+) influx is interrelated to the cycle of Ca(2+) release and uptake by the intracellular Ca(2+) stores during Ca(2+) oscillations in fertilized mouse eggs. In addition to monitoring cytosolic [Ca(2+)] with fura-2, the influx rate was evaluated using Mn(2+) quenching technique, and the change in [Ca(2+)] in the ER lumen was visualized with a targeted fluorescent probe. We found that the influx was stimulated after each transient Ca(2+) release and then diminished gradually to the basal level, and demonstrated that the ER Ca(2+) stores once depleted by Ca(2+) release were gradually refilled until the next Ca(2+) transient to be initiated. Experiments altering extracellular [Ca(2+)] in the middle of Ca(2+) oscillations revealed the dependence of both the refilling rate and the oscillation frequency on the rate of Ca(2+) influx, indicating the crucial role of Ca(2+) influx in determining the intervals of Ca(2+) transients. As for the influx pathway supporting Ca(2+) oscillations to persist, STIM1/Orai1-mediated store-operated Ca(2+) entry (SOCE) may not significantly contribute, since neither known SOCE blockers nor the expression of protein fragments that interfere the interaction between STIM1 and Orai1 inhibited the oscillation frequency or the influx rate.
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Affiliation(s)
- Tooru Takahashi
- Department of Applied Physics and Chemistry, The University of Electro-Communications, Tokyo 182-8585, Japan
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13
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The disruption in actin-perinuclear theca interactions are related with changes induced by cryopreservation observed on sperm chromatin nuclear decondensation of boar semen. Cryobiology 2011; 62:32-9. [DOI: 10.1016/j.cryobiol.2010.11.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 10/19/2010] [Accepted: 11/03/2010] [Indexed: 11/22/2022]
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14
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Impact of marine drugs on cytoskeleton-mediated reproductive events. Mar Drugs 2010; 8:881-915. [PMID: 20479959 PMCID: PMC2866467 DOI: 10.3390/md8040881] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 03/02/2010] [Accepted: 03/23/2010] [Indexed: 12/30/2022] Open
Abstract
Marine organisms represent an important source of novel bioactive compounds, often showing unique modes of action. Such drugs may be useful tools to study complex processes such as reproduction; which is characterized by many crucial steps that start at gamete maturation and activation and virtually end at the first developmental stages. During these processes cytoskeletal elements such as microfilaments and microtubules play a key-role. In this review we describe: (i) the involvement of such structures in both cellular and in vitro processes; (ii) the toxins that target the cytoskeletal elements and dynamics; (iii) the main steps of reproduction and the marine drugs that interfere with these cytoskeleton-mediated processes. We show that marine drugs, acting on microfilaments and microtubules, exert a wide range of impacts on reproductive events including sperm maturation and motility, oocyte maturation, fertilization, and early embryo development.
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15
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Bronson R. What the sperm says and the egg hears - a tale of two proteins and more. Am J Reprod Immunol 2009; 62:357-64. [PMID: 19895373 DOI: 10.1111/j.1600-0897.2009.00758.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
While considerable information exists regarding the early interactions of spermatozoon and egg that lead to successful fertilization, the molecular biology of events that result in the incorporation of the spermatozoon within the cortical ooplasm is largely undefined. There is circumstantial evidence suggesting that this process involves the interactions of specific oolemmal receptors and their ligands on sperm that bear similarities to mechanisms used in phagocytosis by macrophages. We have postulated that the egg may act as a 'non-professional phagocyte' during its association with the spermatozoon. This review surveys those events, provides an historical context, and creates a paradigm for further investigation.
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Affiliation(s)
- Richard Bronson
- Departments of Obstetrics & Gynecology and Pathology, Stony Brook University Medical Center, Stony Brook, NY 11794-8091, USA.
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Luo J, McGinnis LK, Kinsey WH. Fyn kinase activity is required for normal organization and functional polarity of the mouse oocyte cortex. Mol Reprod Dev 2009; 76:819-31. [PMID: 19363790 DOI: 10.1002/mrd.21034] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The objective of the present study was to determine whether Fyn kinase participated in signaling events during sperm-egg interactions, sperm incorporation, and meiosis II. The functional requirement of Fyn kinase activity in these events was tested through the use of the protein kinase inhibitor SKI-606 (Bosutinib) and by analysis of Fyn-null oocytes. Suppression of Fyn kinase signaling prior to fertilization caused disruption of the functional polarity of the oocyte with the result that sperm were able to fuse with the oocyte in the immediate vicinity of the meiotic spindle, a region that normally does not allow sperm fusion. The loss of functional polarity was accompanied by disruption of the microvilli and cortical granule-free zone that normally overlie the meiotic spindle. Changes in the distribution of cortical granules and filamentous actin provided further evidence of disorganization of the oocyte cortex. Rho B, a molecular marker for oocyte polarity, was unaffected by suppression of Fyn activity; however, the polarized association of Par-3 with the cortex overlying the meiotic spindle was completely disrupted. The defects in oocyte polarity in Fyn-null oocytes correlated with a failure of the MII chromosomes to maintain a position close to the oocyte cortex which seemed to underlie the above defects in oocyte polarity. This was associated with a delay in completion of meiosis II. Pronuclei, however, eventually formed and subsequent mitotic cleavages and blastocyst formation occurred normally.
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Affiliation(s)
- Jinping Luo
- Center for Reproductive Sciences, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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17
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Guanine nucleotides in the meiotic maturation of starfish oocytes: regulation of the actin cytoskeleton and of Ca(2+) signaling. PLoS One 2009; 4:e6296. [PMID: 19617909 PMCID: PMC2706993 DOI: 10.1371/journal.pone.0006296] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Accepted: 06/15/2009] [Indexed: 11/19/2022] Open
Abstract
Background Starfish oocytes are arrested at the first prophase of meiosis until they are stimulated by 1-methyladenine (1-MA). The two most immediate responses to the maturation-inducing hormone are the quick release of intracellular Ca2+ and the accelerated changes of the actin cytoskeleton in the cortex. Compared with the later events of oocyte maturation such as germinal vesicle breakdown, the molecular mechanisms underlying the early events involving Ca2+ signaling and actin changes are poorly understood. Herein, we have studied the roles of G-proteins in the early stage of meiotic maturation. Methodology/Principal Findings By microinjecting starfish oocytes with nonhydrolyzable nucleotides that stabilize either active (GTPγS) or inactive (GDPβS) forms of G-proteins, we have demonstrated that: i) GTPγS induces Ca2+ release that mimics the effect of 1-MA; ii) GDPβS completely blocks 1-MA-induced Ca2+; iii) GDPβS has little effect on the amplitude of the Ca2+ peak, but significantly expedites the initial Ca2+ waves induced by InsP3 photoactivation, iv) GDPβS induces unexpectedly striking modification of the cortical actin networks, suggesting a link between the cytoskeletal change and the modulation of the Ca2+ release kinetics; v) alteration of cortical actin networks with jasplakinolide, GDPβS, or actinase E, all led to significant changes of 1-MA-induced Ca2+ signaling. Conclusions/Significance Taken together, these results indicate that G-proteins are implicated in the early events of meiotic maturation and support our previous proposal that the dynamic change of the actin cytoskeleton may play a regulatory role in modulating intracellular Ca2+ release.
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18
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Ito M, Shikano T, Kuroda K, Miyazaki S. Relationship between nuclear sequestration of PLCζ and termination of PLCζ-induced Ca2+ oscillations in mouse eggs. Cell Calcium 2008; 44:400-10. [DOI: 10.1016/j.ceca.2008.02.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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19
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Peddinti D, Nanduri B, Kaya A, Feugang JM, Burgess SC, Memili E. Comprehensive proteomic analysis of bovine spermatozoa of varying fertility rates and identification of biomarkers associated with fertility. BMC SYSTEMS BIOLOGY 2008; 2:19. [PMID: 18294385 PMCID: PMC2291030 DOI: 10.1186/1752-0509-2-19] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 02/22/2008] [Indexed: 11/10/2022]
Abstract
BACKGROUND Male infertility is a major problem for mammalian reproduction. However, molecular details including the underlying mechanisms of male fertility are still not known. A thorough understanding of these mechanisms is essential for obtaining consistently high reproductive efficiency and to ensure lower cost and time-loss by breeder. RESULTS Using high and low fertility bull spermatozoa, here we employed differential detergent fractionation multidimensional protein identification technology (DDF-Mud PIT) and identified 125 putative biomarkers of fertility. We next used quantitative Systems Biology modeling and canonical protein interaction pathways and networks to show that high fertility spermatozoa differ from low fertility spermatozoa in four main ways. Compared to sperm from low fertility bulls, sperm from high fertility bulls have higher expression of proteins involved in: energy metabolism, cell communication, spermatogenesis, and cell motility. Our data also suggests a hypothesis that low fertility sperm DNA integrity may be compromised because cell cycle: G2/M DNA damage checkpoint regulation was most significant signaling pathway identified in low fertility spermatozoa. CONCLUSION This is the first comprehensive description of the bovine spermatozoa proteome. Comparative proteomic analysis of high fertility and low fertility bulls, in the context of protein interaction networks identified putative molecular markers associated with high fertility phenotype.
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Affiliation(s)
- Divyaswetha Peddinti
- Department of Basic Sciences, Mississippi State University, Mississippi State, MS 39762, USA.
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20
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Meng XQ, Zheng KG, Yang Y, Jiang MX, Zhang YL, Sun QY, Li YL. Proline-rich tyrosine kinase2 is involved in F-actin organization during in vitro maturation of rat oocyte. Reproduction 2007; 132:859-67. [PMID: 17127746 DOI: 10.1530/rep.1.01212] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Microfilaments (actin filaments) regulate various dynamic events during meiotic maturation. Relatively, little is known about the regulation of microfilament organization in mammalian oocytes. Proline-rich tyrosine kinase2 (Pyk2), a protein tyrosine kinase related to focal adhesion kinase (FAK) is essential in actin filaments organization. The present study was to examine the expression and localization of Pyk2, and in particular, its function during rat oocyte maturation. For the first time, by using Western blot and confocal laser scanning microscopy, we detected the expression of Pyk2 in rat oocytes and found that Pyk2 and Try402 phospho-Pyk2 were localized uniformly at the cell cortex and surrounded the germinal vesicle (GV) or the condensed chromosomes at the GV stage or after GV breakdown. At the metaphase and the beginning of anaphase, Pyk2 distributed asymmetrically both in the ooplasm and the cortex with a marked staining associated with the chromosomes and the region overlying the meiotic spindle. At telophase, Pyk2 was observed in the cleavage furrows in addition to its cortex and cytoplasm localization. The dynamics of Pyk2 were similar to that of F-actin, and this kinase was found to co-localize with microfilaments in several developmental stages during rat oocyte maturation. Microinjection of Pyk2 antibody demolished the microfilaments assembly and also inhibited the first polar body (PB1) emission. These findings suggest an important role of Pyk2 for rat oocyte maturation by regulating the organization of actin filaments.
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Affiliation(s)
- Xiao-Qian Meng
- Key Laboratory of Animal Resistance, College of Life Science, Shandong Normal University, 88 East Wenhua Road, Jinan 250002, People's Republic of China
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21
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Halet G, Carroll J. Rac activity is polarized and regulates meiotic spindle stability and anchoring in mammalian oocytes. Dev Cell 2007; 12:309-17. [PMID: 17276347 DOI: 10.1016/j.devcel.2006.12.010] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Revised: 11/23/2006] [Accepted: 12/19/2006] [Indexed: 01/24/2023]
Abstract
Mammalian meiotic divisions are asymmetrical and generate a large oocyte and two small polar bodies. This asymmetry results from the anchoring of the meiotic spindle to the oocyte cortex and subsequent cortical reorganization, but the mechanisms involved are poorly understood. We investigated the role of Rac in oocyte meiosis by using a fluorescent reporter for Rac-GTP. We find that Rac-GTP is polarized in the cortex overlying the meiotic spindle. Polarization of Rac activation occurs during spindle migration and is promoted by the proximity of chromatin to the cortex. Inhibition of Rac during oocyte maturation caused a permanent block at prometaphase I and spindle elongation. In metaphase II-arrested oocytes, Rac inhibition caused the spindle to detach from the cortex and prevented polar body emission after activation. These results demonstrate that Rac-GTP plays a major role in oocyte meiosis, via the regulation of spindle stability and anchoring to the cortex.
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Affiliation(s)
- Guillaume Halet
- Department of Physiology, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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22
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Kuroda K, Ito M, Shikano T, Awaji T, Yoda A, Takeuchi H, Kinoshita K, Miyazaki S. The Role of X/Y Linker Region and N-terminal EF-hand Domain in Nuclear Translocation and Ca2+ Oscillation-inducing Activities of Phospholipase Cζ, a Mammalian Egg-activating Factor. J Biol Chem 2006; 281:27794-805. [PMID: 16854985 DOI: 10.1074/jbc.m603473200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sperm-specific phospholipase C-zeta (PLCzeta) causes intracellular Ca(2+) oscillations and thereby egg activation and is accumulated into the formed pronucleus (PN) when expressed in mouse eggs by injection of cRNA encoding PLCzeta, which consists of four EF-hand domains (EF1-EF4) in the N terminus, X and Y catalytic domains, and C-terminal C2 domain. Those activities were analyzed by expressing PLCzeta mutants tagged with fluorescent protein Venus by injection of cRNA into unfertilized eggs or 1-cell embryos after fertilization. Nuclear localization signal (NLS) existed at 374-381 in the X/Y linker region. Nuclear translocation was lost by replacement of Arg(376), Lys(377), Arg(378), Lys(379), or Lys(381) with glutamate, whereas Ca(2+) oscillations were conserved. Nuclear targeting was also absent for point mutation of Lys(299) and/or Lys(301) in the C terminus of X domain, or Trp(13), Phe(14), or Val(18) in the N terminus of EF1. Ca(2+) oscillation-inducing activity was lost by the former mutation and was remarkably inhibited by the latter. A short sequence 374-383 fused with Venus showed active translocation into the nucleus of COS-7 cells, but 296-309 or 1-19 did not. Despite the presence of these special regions, both activities were deprived by deletion of not only EF1 but also EF2-4 or C2 domain. Thus, PLCzeta is driven into the nucleus primarily by the aid of NLS and putative regulatory sites, but coordinated three-dimensional structure, possibly formed by a folding in the X/Y linker and close EF/C2 contact as in PLCdelta1, seems to be required not only for enzymatic activity but also for nuclear translocation ability.
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Affiliation(s)
- Keiji Kuroda
- Department of Physiology, Tokyo Women's Medical University School of Medicine, Tokyo 162-8666, Japan
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23
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Sun QY, Schatten H. Regulation of dynamic events by microfilaments during oocyte maturation and fertilization. Reproduction 2006; 131:193-205. [PMID: 16452714 DOI: 10.1530/rep.1.00847] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Actin filaments (microfilaments) regulate various dynamic events during oocyte meiotic maturation and fertilization. In most species, microfilaments are not required for germinal vesicle breakdown and meiotic spindle formation, but they mediate peripheral nucleus (chromosome) migration, cortical spindle anchorage, homologous chromosome separation, cortex development/maintenance, polarity establishment, and first polar body emission during oocyte maturation. Peripheral cortical granule migration is controlled by microfilaments, while mitochondria movement is mediated by microtubules. During fertilization, microfilaments are involved in sperm incorporation, spindle rotation (mouse), cortical granule exocytosis, second polar body emission and cleavage ring formation, but are not required for pronuclear apposition (except for the mouse). Many of the events are driven by the dynamic interactions between myosin and actin filaments whose polymerization is regulated by RhoA, Cdc42, Arp2/3 and other signaling molecules. Studies have also shown that oocyte cortex organization and polarity formation mediated by actin filaments are regulated by mitogen-activated protein kinase, myosin light-chain kinase, protein kinase C and its substrate p-MARKS as well as PAR proteins. The completion of several dynamic events, including homologous chromosome separation, spindle anchorage, spindle rotation, vesicle organelle transport and pronuclear apposition (mouse), requires interactions between microfilaments and microtubules, but determination of how the two systems of the cytoskeleton precisely cross-link, and which proteins link microfilaments to microtubules to perform functions in eggs, requires further studies. Finally, the meaning of microfilament-mediated oocyte polarity versus embryo polarity and embryo development in different species (Drosophila, Xenopus and mouse) is discussed.
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Affiliation(s)
- Qing-Yuan Sun
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China
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24
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Shirakawa H, Ito M, Sato M, Umezawa Y, Miyazaki S. Measurement of intracellular IP3 during Ca2+ oscillations in mouse eggs with GFP-based FRET probe. Biochem Biophys Res Commun 2006; 345:781-8. [PMID: 16701560 DOI: 10.1016/j.bbrc.2006.04.133] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Accepted: 04/24/2006] [Indexed: 10/24/2022]
Abstract
Intracellular Ca2+ oscillations in fertilized mammalian eggs, the key signal that stimulates egg activation and early embryonic development, are regulated by inositol 1,4,5-trisphosphate (IP3) signaling pathway. We investigated temporal changes in intracellular IP3 concentration ([IP3]i) in mouse eggs, using a fluorescent probe based on fluorescence resonance energy transfer between two green fluorescent protein variants, during Ca2+ oscillations induced by fertilization or expression of phospholipase Czeta (PLCzeta), an egg-activating sperm factor candidate. Fluorescence measurements suggested the elevation of [IP3]i in fertilized eggs, and the enhancement of PLCzeta-mediated IP3 production by cytoplasmic Ca2+ was observed during Ca2+ oscillations or in response to CaCl2 microinjection. The results supported the view that PLCzeta is the sperm factor to stimulate IP3 pathway, and suggested that high Ca2+ sensitivity of PLCzeta activity and positive feedback from released Ca2+ are important for triggering and maintaining Ca2+ oscillations.
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Affiliation(s)
- Hideki Shirakawa
- Department of Applied Physics and Chemistry, The University of Electro-Communications, Tokyo 182-8585, Japan.
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25
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Abstract
Fertilization calcium waves are introduced, and the evidence from which we can infer general mechanisms of these waves is presented. The two main classes of hypotheses put forward to explain the generation of the fertilization calcium wave are set out, and it is concluded that initiation of the fertilization calcium wave can be most generally explained in invertebrates by a mechanism in which an activating substance enters the egg from the sperm on sperm-egg fusion, activating the egg by stimulating phospholipase C activation through a src family kinase pathway and in mammals by the diffusion of a sperm-specific phospholipase C from sperm to egg on sperm-egg fusion. The fertilization calcium wave is then set into the context of cell cycle control, and the mechanism of repetitive calcium spiking in mammalian eggs is investigated. Evidence that calcium signals control cell division in early embryos is reviewed, and it is concluded that calcium signals are essential at all three stages of cell division in early embryos. Evidence that phosphoinositide signaling pathways control the resumption of meiosis during oocyte maturation is considered. It is concluded on balance that the evidence points to a need for phosphoinositide/calcium signaling during resumption of meiosis. Changes to the calcium signaling machinery occur during meiosis to enable the production of a calcium wave in the mature oocyte when it is fertilized; evidence that the shape and structure of the endoplasmic reticulum alters dynamically during maturation and after fertilization is reviewed, and the link between ER dynamics and the cytoskeleton is discussed. There is evidence that calcium signaling plays a key part in the development of patterning in early embryos. Morphogenesis in ascidian, frog, and zebrafish embryos is briefly described to provide the developmental context in which calcium signals act. Intracellular calcium waves that may play a role in axis formation in ascidian are discussed. Evidence that the Wingless/calcium signaling pathway is a strong ventralizing signal in Xenopus, mediated by phosphoinositide signaling, is adumbrated. The central role that calcium channels play in morphogenetic movements during gastrulation and in ectodermal and mesodermal gene expression during late gastrulation is demonstrated. Experiments in zebrafish provide a strong indication that calcium signals are essential for pattern formation and organogenesis.
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Affiliation(s)
- Michael Whitaker
- Institute of Cell & Molecular Biosciences, Faculty of Medical Sciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK.
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26
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Matson S, Markoulaki S, Ducibella T. Antagonists of myosin light chain kinase and of myosin II inhibit specific events of egg activation in fertilized mouse eggs. Biol Reprod 2005; 74:169-76. [PMID: 16207836 DOI: 10.1095/biolreprod.105.046409] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Although recent studies have demonstrated the importance of calcium/calmodulin (Ca(2+)/CAM) signaling in mammalian fertilization, many targets of Ca(2+)/CAM have not been investigated and represent potentially important regulatory pathways to transduce the Ca2+ signal that is responsible for most events of egg activation. A well-established Ca(2+)/CAM-dependent enzyme is myosin light chain kinase (MYLK2), the downstream target of which is myosin II, an isoform of myosin known to be important in cytokinesis. In fertilized mouse eggs, established inhibitors of MYLK2 and myosin II were investigated for their effects on events of egg activation. The MYLK2 antagonist, ML-7, did not decrease the activity of Ca(2+)/CAM protein kinase II or the elevation of intracellular Ca2+, and it did not delay the onset of Ca2+ oscillations. In contrast, ML-7 inhibited second polar body (PB) formation in a dose-dependent manner and reduced cortical granule (CG) exocytosis by a mean of approximately 50%. The myosin II isoform-specific inhibitor, blebbistatin, had similar inhibitory effects. Although both antagonists had no effect on anaphase onset, they inhibited second PB formation by preventing spindle rotation before telophase II and normal contractile ring constriction. To our knowledge, this is the first report that MYLK2 and myosin II are involved in regulating the position of the meiotic spindle, formation of the second PB, and CG exocytosis. The present results suggest that MYLK2 is one of a family of CAM-dependent proteins that act as multifunctional regulators and transduce the Ca2+ signal at fertilization.
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Affiliation(s)
- Sara Matson
- Department of Obstetrics and Gynecology, Tufts-New England Medical Center, Boston, MA 02111, USA
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27
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Sone Y, Ito M, Shirakawa H, Shikano T, Takeuchi H, Kinoshita K, Miyazaki S. Nuclear translocation of phospholipase C-zeta, an egg-activating factor, during early embryonic development. Biochem Biophys Res Commun 2005; 330:690-4. [PMID: 15809052 DOI: 10.1016/j.bbrc.2005.03.032] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2005] [Indexed: 11/28/2022]
Abstract
Phospholipase C-zeta (PLCzeta), a strong candidate of the egg-activating sperm factor, causes intracellular Ca2+ oscillations and egg activation, and is subsequently accumulated into the pronucleus (PN), when expressed in mouse eggs by injection of RNA encoding PLCzeta. Changes in the localization of expressed PLCzeta were investigated by tagging with a fluorescent protein. PLCzeta began to translocate into the PN formed at 5-6 h after RNA injection and increased there. Observation in the same embryo revealed that PLCzeta in the PN dispersed to the cytoplasm upon nuclear envelope breakdown and translocated again into the nucleus after cleavage. The dynamics was found in the second mitosis as well. When RNA was injected into fertilization-originated 1-cell embryos or blastomere(s) of 2-8-cell embryos, the nuclear localization of expressed PLCzeta was recognized in every embryo up to blastocyst. Thus, PLCzeta exhibited alternative cytoplasm/nucleus localization during development. This supports the view that the sperm factor could control cell cycle-dependent generation of Ca2+ oscillations in early embryogenesis.
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Affiliation(s)
- Yoshie Sone
- Department of Physiology, Tokyo Women's Medical University School of Medicine, Tokyo 162-8666, Japan
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28
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Deng M, Williams CJ, Schultz RM. Role of MAP kinase and myosin light chain kinase in chromosome-induced development of mouse egg polarity. Dev Biol 2005; 278:358-66. [PMID: 15680356 DOI: 10.1016/j.ydbio.2004.11.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Revised: 11/08/2004] [Accepted: 11/11/2004] [Indexed: 11/24/2022]
Abstract
During maturation, the mouse oocyte is transformed into a highly polarized egg, characterized by an actin cap and cortical granule-free domain (CGFD) overlying the meiotic spindle that is in close proximity to the cortex. The presence of spindle/chromosomes or microinjected sperm chromatin in the cortical region initiates this cortical reorganization, but the pathway is unknown. We report that cortical reorganization induced by microinjected sperm chromatin is blocked by inhibitors of microfilament assembly or disassembly. Active mitogen-activated protein kinase (MAPK), which becomes enriched in the region of sperm chromatin, is required for cortical reorganization, because microinjected sperm chromatin fails to induce cortical reorganization in Mos-/- eggs, which lack MAPK activity. Last, myosin light chain kinase (MLCK), which can be directly phosphorylated and activated by MAPK, appears involved, because the MLCK inhibitors ML-7 and Peptide 18 prevent sperm chromatin-induced cortical reorganization. These results provide new insights into how cortical reorganization occurs independently of extracellular signals to generate egg polarity.
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Affiliation(s)
- Manqi Deng
- Department of Biology, University of Pennsylvania, 415 South University Avenue, Philadelphia, PA 19104-6018, USA
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29
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Breitbart H, Cohen G, Rubinstein S. Role of actin cytoskeleton in mammalian sperm capacitation and the acrosome reaction. Reproduction 2005; 129:263-8. [PMID: 15749953 DOI: 10.1530/rep.1.00269] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In order to fertilize, the mammalian spermatozoa should reside in the female reproductive tract for several hours, during which they undergo a series of biochemical modifications collectively called capacitation. Only capacitated sperm can undergo the acrosome reaction after binding to the egg zona pellucida, a process which enables sperm to penetrate into the egg and fertilize it. Polymerization of globular (G)-actin to filamentous (F)-actin occurs during capacitation, depending on protein kinase A activation, protein tyrosine phosphorylation, and phospholipase D activation. F-actin formation is important for the translocation of phospholipase C from the cytosol to the sperm plasma membrane during capacitation. Prior to the occurrence of the acrosome reaction, the F-actin should undergo depolymerization, a necessary process which enables the outer acrosomal membrane and the overlying plasma membrane to come into close proximity and fuse. The binding of the capacitated sperm to the zona pellucida induces a fast increase in sperm intracellular calcium, activation of actin severing proteins which break down the actin fibers, and allows the acrosome reaction to take place.
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Affiliation(s)
- Haim Breitbart
- Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
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30
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Jellerette T, Kurokawa M, Lee B, Malcuit C, Yoon SY, Smyth J, Vermassen E, De Smedt H, Parys JB, Fissore RA. Cell cycle-coupled [Ca(2+)](i) oscillations in mouse zygotes and function of the inositol 1,4,5-trisphosphate receptor-1. Dev Biol 2004; 274:94-109. [PMID: 15355791 DOI: 10.1016/j.ydbio.2004.06.020] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Revised: 06/12/2004] [Accepted: 06/12/2004] [Indexed: 11/20/2022]
Abstract
Sperm entry in mammalian eggs initiates oscillations in the concentration of free calcium ([Ca(2+)](i)). In mouse eggs, oscillations start at metaphase II (MII) and conclude as the zygotes progress into interphase and commence pronuclear (PN) formation. The inositol 1,4,5-trisphosphate receptor (IP(3)R-1), which underlies the oscillations, undergoes degradation during this transition, suggesting that one or more of the eggs' Ca(2+)-releasing machinery components may be regulated in a cell cycle-dependent manner, thereby coordinating [Ca(2+)](i) responses with the cell cycle. To ascertain the site(s) of interaction, we initiated oscillations at different stages of the cell cycle in zygotes with different IP(3)R-1 mass. In addition to sperm, we used two other agonists: porcine sperm factor (pSF), which stimulates production of IP(3), and adenophostin A, a non-hydrolyzable analogue of IP(3). None of the agonists tested induced oscillations at interphase, suggesting that neither decreased IP(3)R-1 mass nor lack of production or excessive IP(3) degradation can account for the insensitivity to IP(3) at this stage. Moreover, the releasable Ca(2+) content of the stores did not change by interphase, but it did decrease by first mitosis. More importantly, experiments revealed that IP(3)R-1 sensitivity and possibly IP(3) binding were altered at interphase, and our data demonstrate stage-specific IP(3)R-1 phosphorylation by M-phase kinases. Accordingly, increasing the activity of M-phase kinases restored the oscillatory-permissive state in zygotes. We therefore propose that the restriction of oscillations in mouse zygotes to the metaphase stage may be coordinated at the level of IP(3)R-1 and that this involves cell cycle stage-specific receptor phosphorylation.
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Affiliation(s)
- Teru Jellerette
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
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31
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Tutuncu L, Stein P, Ord TS, Jorgez CJ, Williams CJ. Calreticulin on the mouse egg surface mediates transmembrane signaling linked to cell cycle resumption. Dev Biol 2004; 270:246-60. [PMID: 15136153 DOI: 10.1016/j.ydbio.2004.02.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2003] [Revised: 02/09/2004] [Accepted: 02/11/2004] [Indexed: 11/25/2022]
Abstract
Calreticulin, a protein best known as an endoplasmic reticulum chaperone, also is found on the extracellular plasma membrane surface of many cell types where it serves as a mediator of adhesion and as a regulator of the immune response. In this report, we demonstrate that calreticulin is present on the extracellular surface of the mouse egg plasma membrane and is increased in the perivitelline space after egg activation. The extracellular calreticulin appears to be secreted by vesicles in the egg cortex that are distinct from cortical granules. An anticalreticulin antibody binds to extracellular calreticulin on live eggs and inhibits sperm-egg binding but not fusion. In addition, engagement of cell surface calreticulin by incubation of mouse eggs in the presence of anticalreticulin antibodies results in alterations in the localization of cortical actin and the resumption of meiosis as indicated by alterations in chromatin configuration, decreases in cdc2/cyclin B1 and MAP kinase activities, and pronuclear formation. These events occur in the absence of any observable alterations in intercellular calcium. These data demonstrate that calreticulin functionally interacts with the egg cytoskeleton and can mediate transmembrane signaling linked to cell cycle resumption. These studies suggest a role for calreticulin as a lectin that may be involved in signal transduction events during or after sperm-egg interactions at fertilization.
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Affiliation(s)
- Levent Tutuncu
- Center for Research on Reproduction and Women's Health, University of Pennsylvania, Philadelphia, PA 19104, USA
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Yoda A, Oda S, Shikano T, Kouchi Z, Awaji T, Shirakawa H, Kinoshita K, Miyazaki S. Ca2+ oscillation-inducing phospholipase C zeta expressed in mouse eggs is accumulated to the pronucleus during egg activation. Dev Biol 2004; 268:245-57. [PMID: 15063165 DOI: 10.1016/j.ydbio.2003.12.028] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2003] [Revised: 12/22/2003] [Accepted: 12/22/2003] [Indexed: 11/23/2022]
Abstract
Sperm-specific phospholipase C zeta (PLC zeta) is known to induce intracellular Ca(2+) oscillations and egg activation when expressed in mouse eggs by injection of RNA encoding PLC zeta. We investigated the expression level and spatial distribution of PLC zeta in the egg in real time and in relation to the initiation and termination of Ca(2+) oscillations by monitoring fluorescence of a yellow fluorescent protein 'Venus' fused with PLC zeta. Ca(2+) oscillations similar to those at fertilization were induced at 40-50 min after RNA injection, when expressed PLC zeta reached 10-40 x 10(-15) g in the egg. PLC zeta-Venus increased up to 3 h and attained a steady level at 4-5 h. Interestingly, PLC zeta-Venus is accumulated to the pronucleus (PN) formed at 5-6 h and continuously increased there. Ca(2+) oscillations stopped in most eggs before initiation of the accumulation. A variant of PLC zeta that lacks three EF hand domains was much less effective in induction of Ca(2+) oscillations and little accumulated in the pronucleus, indicating a critical role of those domains. The ability of the accumulation to the pronucleus qualifies PLC zeta for a strong candidate of the Ca(2+) oscillation-inducing sperm factor, which is introduced into the ooplasm upon sperm-egg fusion and concentrated to the pronucleus after inducing egg activation.
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Affiliation(s)
- Ayako Yoda
- Department of Physiology, Tokyo Women's Medical University School of Medicine, Shinjuku-ku, Tokyo 162-8666, Japan
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Kouchi Z, Fukami K, Shikano T, Oda S, Nakamura Y, Takenawa T, Miyazaki S. Recombinant phospholipase Czeta has high Ca2+ sensitivity and induces Ca2+ oscillations in mouse eggs. J Biol Chem 2003; 279:10408-12. [PMID: 14701816 DOI: 10.1074/jbc.m313801200] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sperm-specific phospholipase Czeta (PLCzeta) is known to induce intracellular Ca(2+) oscillations and subsequent early embryonic development when expressed in mouse eggs by injection of RNA encoding PLCzeta (Saunders, C. M., Larman, M. G., Parrington, J., Cox, L. J., Royse, J., Blayney, L. M., Swann, K., and Lai, F. A. (2002) Development 129, 3533-3544). The present study addressed characteristics of purified mouse PLCzeta protein that was synthesized using the baculovirus/Sf9 cell expression system. Microinjection of recombinant PLCzeta protein into mouse eggs induced serial Ca(2+) spikes quite similar to those produced by the injection of sperm extract, probably because of repetitive Ca(2+) release from the endoplasmic reticulum caused by continuously produced inositol 1,4,5-trisphosphate. Recombinant PLCdelta1 also induced Ca(2+) oscillations, but a 20-fold higher concentration was required compared with PLCzeta. In the enzymatic assay of phosphatidylinositol 4,5-bisphosphate hydrolyzing activity in vitro at various calcium ion concentrations ([Ca(2+)]), PLCzeta exhibited a significant activity at [Ca(2+)] as low as 10 nm and had 70% maximal activity at 100 nm [Ca(2+)] that is usually the basal intracellular calcium ion concentration level of cells. On the other hand, the activity of PLCdelta1 increased at a [Ca(2+)] between 1 and 30 microm. EC(50) was 52 nm for PLCzeta and 5.7 microm for PLCdelta1. Thus, PLCzeta has an approximately 100-fold higher Ca(2+) sensitivity than PLCdelta1. The ability of purified PLCzeta protein to induce Ca(2+) oscillations qualifies PLCzeta as a proper candidate of the mammalian egg-activating sperm factor. Furthermore, such a high Ca(2+) sensitivity of PLC activity as PLCzeta that can be active in cells at the resting state is thought to be an appropriate characteristic of the sperm factor, which is introduced into the ooplasm upon sperm-egg fusion, triggers Ca(2+) release first, and maintains Ca(2+) oscillations.
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Affiliation(s)
- Zen Kouchi
- Department of Physiology, Tokyo Women's Medical University School of Medicine, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
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