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Bahety D, Böke E, Rodríguez-Nuevo A. Mitochondrial morphology, distribution and activity during oocyte development. Trends Endocrinol Metab 2024:S1043-2760(24)00064-X. [PMID: 38599901 DOI: 10.1016/j.tem.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 04/12/2024]
Abstract
Mitochondria have a crucial role in cellular function and exhibit remarkable plasticity, adjusting both their structure and activity to meet the changing energy demands of a cell. Oocytes, female germ cells that become eggs, undergo unique transformations: the extended dormancy period, followed by substantial increase in cell size and subsequent maturation involving the segregation of genetic material for the next generation, present distinct metabolic challenges necessitating varied mitochondrial adaptations. Recent findings in dormant oocytes challenged the established respiratory complex hierarchies and underscored the extent of mitochondrial plasticity in long-lived oocytes. In this review, we discuss mitochondrial adaptations observed during oocyte development across three vertebrate species (Xenopus, mouse, and human), emphasising current knowledge, acknowledging limitations, and outlining future research directions.
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Affiliation(s)
- Devesh Bahety
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Elvan Böke
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain.
| | - Aida Rodríguez-Nuevo
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.
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Nouri C, Tuszynski JA, Wiebe MW, Gordon R. Simulation of the effects of microtubules in the cortical rotation of amphibian embryos in normal and zero gravity. Biosystems 2012; 109:444-9. [PMID: 22677068 DOI: 10.1016/j.biosystems.2012.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 05/18/2012] [Accepted: 05/18/2012] [Indexed: 11/15/2022]
Abstract
This paper reports the results of computer modeling of microtubules that end up in the cortical region of a one-cell amphibian embryo, prior to the first cell division. Microtubules are modeled as initially randomly oriented semi-flexible rods, represented by several lines of point-masses interacting with one another like masses on springs with longitudinal and transverse stiffness. They are also considered to be space-filling rods floating in a viscous fluid (cytoplasm) experiencing drag forces and buoyancy from the fluid under a variable gravity field to test gravitational effects. Their randomly distributed interactions with the surrounding spherical container (the cell membrane) have a statistical nonzero average that creates a torque causing a rotational displacement between the cytoplasm and the rigid cortex. The simulation has been done for zero and normal gravity and it validates the observation that cortical rotation occurs in microgravity as well as on Earth. The speed of rotation depends on gravity, but is still substantial in microgravity.
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Affiliation(s)
- Comron Nouri
- Physics Division, Department of Natural & Environmental Science, Front Range Community College, Larimer Campus, 4616 S. Shields Street, Fort Collins, CO 80526, USA.
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Kniazeva M, Shen H, Euler T, Wang C, Han M. Regulation of maternal phospholipid composition and IP(3)-dependent embryonic membrane dynamics by a specific fatty acid metabolic event in C. elegans. Genes Dev 2012; 26:554-66. [PMID: 22426533 DOI: 10.1101/gad.187054.112] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Natural fatty acids (FAs) exhibit vast structural diversity, but the functional importance of FA variations and the mechanism by which they contribute to a healthy lipid composition in animals remain largely unexplored. A large family of acyl-CoA synthetases (ACSs) regulates FA metabolism by esterifying FA to coenyzme A. However, little is known about how particular FA-ACS combinations affect lipid composition and specific cellular functions. We analyzed how the activity of ACS-1 on branched chain FA C17ISO impacts maternal lipid content, signal transduction, and development in Caenorhabditis elegans embryos. We show that expression of ACS-1 in the somatic gonad guides the incorporation of C17ISO into certain phospholipids and thus regulates the phospholipid composition in the zygote. Disrupting this ACS-1 function causes striking defects in complex membrane dynamics, including exocytosis and cytokinesis, leading to early embryonic lethality. These defects are suppressed by hyperactive IP(3) signaling, suggesting that C17ISO and ACS-1 functions are necessary for optimal IP(3) signaling essential for early embryogenesis. This study shows a novel role of branched chain FAs whose functions in humans and animals are unknown and uncovers a novel intercellular regulatory pathway linking a specific FA-ACS interaction to specific developmental events.
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Affiliation(s)
- Marina Kniazeva
- Howard Hughes Medical Institute, Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
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Spectrin labeling during oogenesis in zebrafish (Danio rerio). Acta Histochem 2012; 114:177-81. [PMID: 21531010 DOI: 10.1016/j.acthis.2011.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Revised: 03/25/2011] [Accepted: 03/27/2011] [Indexed: 11/20/2022]
Abstract
Progression through mitosis and meiosis during early zebrafish ovarian development is accompanied by highly regulated series of transformations in the architecture of oocytes. These cytoskeletal-dependent membrane events may be assumed to be brought about by deployment of proteins. While the cytoskeleton and its associated proteins play a pivotal role in each of these developmental transitions, it remains unclear how specific cytoskeletal proteins participate in regulating diverse processes of oocyte development in zebrafish. Results from this study show that a pool of spectrin accumulates during oogenesis and parallels an increase in volume of oocytes at pre-vitellogenic stages of development. Spectrin labeling is restricted to the surface of oogonia, the cortex of post-pachytene oocytes and later accumulates on the cytoplasm of pre-vitellogenic and vitellogenic oocytes. Results here suggest a correlation between spectrin labeling, increased cytoplasm volume of oocytes, an increase in the number of nucleoli and accumulation of cytoplasmic organelles. Overall, these results suggest that synthesis and storage of spectrin during pre-vitellogenic stages of oogenesis primes the egg with a pre-established pool of membrane-cytoskeletal precursors for use during embryogenesis, and that the presence of spectrin at the oocyte sub-cortex is essential for maintaining oocyte structure.
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Sindelka R, Sidova M, Svec D, Kubista M. Spatial expression profiles in the Xenopus laevis oocytes measured with qPCR tomography. Methods 2010; 51:87-91. [DOI: 10.1016/j.ymeth.2009.12.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 12/16/2009] [Accepted: 12/18/2009] [Indexed: 11/27/2022] Open
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Dharia S, Ayliffe HE, Rabbitt RD. Single cell electric impedance topography: mapping membrane capacitance. LAB ON A CHIP 2009; 9:3370-7. [PMID: 19904403 PMCID: PMC3004743 DOI: 10.1039/b912881f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Single-cell electric impedance topography (sceTopo), a technique introduced here, maps the spatial distribution of capacitance (i.e. displacement current) associated with the membranes of isolated, living cells. Cells were positioned in the center of a circular recording chamber surrounded by eight electrodes. Electrodes were evenly distributed on the periphery of the recording chamber. Electric impedance measured between adjacent electrode pairs (10 kHz-5 MHz) was used to construct topographical maps of the spatial distribution of membrane capacitance. Xenopus Oocytes were used as a model cell to develop sceTopo because these cells consist of two visually distinguishable hemispheres, each with distinct membrane composition and structure. Results showed significant differences in the imaginary component of the impedance between the two oocyte hemispheres. In addition, the same circumferential array was used to map the size of the extracellular electrical shunt path around the cell, providing a means to estimate the location and shape of the cell in the recording chamber.
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Affiliation(s)
- Sameera Dharia
- Department of Bioengineering, University of Utah, 72 South Central Campus Dr., Rm. 2646, Salt Lake City, UT, 84112, USA. ; ; Tel: +1 801 581-6968
| | | | - Richard D. Rabbitt
- Department of Bioengineering, University of Utah, 72 South Central Campus Dr., Rm. 2646, Salt Lake City, UT, 84112, USA. ; ; Tel: +1 801 581-6968
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7
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Abstract
Background To obtain non-relative measures of cell proteins, purified preparations of the same proteins are used as standards in Western blots. We have previously quantified SV40 large T antigen expressed over a several fold range in different cell lines and correlated the average number of molecules to average fluorescence obtained by cytometry and determined cell cycle phase related expression by calculation from multi-parametric cytometry data. Using a modified approach, we report quantification of endogenous cyclin B1 and generation of the cell cycle time related expression profile. Methodology Recombinant cyclin B1 was purified from a baculovirus lysate using an antibody affinity column and concentrated. We created fixed cell preparations from nocodazole-treated (high cyclin B1) and serum starved (low cyclin B1) PC3 cells that were either lyophilized (for preservation) or solubilized. The lysates and purified cyclin B1 were subjected to Western blotting; the cell preparations were subjected to cytometry, and fluorescence was correlated to molecules. Three untreated cell lines (K562, HeLa, and RKO) were prepared for cytometry without lyophilization and also prepared for Western blotting. These were quantified by Western blotting and by cytometry using the standard cell preparations. Results The standard cell preparations had 1.5×105 to 2.5×106 molecules of cyclin B1 per cell on average (i.e., 16-fold range). The average coefficient of variation was 24%. Fluorescence varied 12-fold. The relationship between molecules/cell (Western blot) and immunofluorescence (cytometry) was linear (r2 = 0.87). Average cyclin B1 levels for the three untreated cell lines determined by Western blotting and cytometry agreed within a factor of 2. The non-linear rise in cyclin B1 in S phase was quantified from correlated plots of cyclin B1 and DNA content. The peak levels achieved in G2 were similar despite differences in lineage, growth conditions, and rates of increase through the cell cycle (range: 1.6–2.2×106 molecules per cell). Conclusions Net cyclin B1 expression begins in G1 in human somatic cells lines; increases non-linearly with variation in rates of accumulation, but peaks at similar peak values in different cell lines growing under different conditions. This suggests tight quantitative end point control.
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Affiliation(s)
- Phyllis S. Frisa
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - James W. Jacobberger
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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Cartwright JH, Piro O, Tuval I. Fluid dynamics in developmental biology: moving fluids that shape ontogeny. HFSP JOURNAL 2008; 3:77-93. [PMID: 19794816 PMCID: PMC2707792 DOI: 10.2976/1.3043738] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 10/31/2008] [Indexed: 12/19/2022]
Abstract
Human conception, indeed fertilization in general, takes place in a fluid, but what role does fluid dynamics have during the subsequent development of an organism? It is becoming increasingly clear that the number of genes in the genome of a typical organism is not sufficient to specify the minutiae of all features of its ontogeny. Instead, genetics often acts as a choreographer, guiding development but leaving some aspects to be controlled by physical and chemical means. Fluids are ubiquitous in biological systems, so it is not surprising that fluid dynamics should play an important role in the physical and chemical processes shaping ontogeny. However, only in a few cases have the strands been teased apart to see exactly how fluid forces operate to guide development. Here, we review instances in which the hand of fluid dynamics in developmental biology is acknowledged, both in human development and within a wider biological context, together with some in which fluid dynamics is notable but whose workings have yet to be understood, and we provide a fluid dynamicist's perspective on possible avenues for future research.
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Affiliation(s)
- Julyan H.E. Cartwright
- Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Campus Fuentenueva, E-18071 Granada, Spain
| | - Oreste Piro
- Departamento de Física e Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (CSIC-UIB), Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
| | - Idan Tuval
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom
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Sindelka R, Jonák J, Hands R, Bustin SA, Kubista M. Intracellular expression profiles measured by real-time PCR tomography in the Xenopus laevis oocyte. Nucleic Acids Res 2007; 36:387-92. [PMID: 18039714 PMCID: PMC2241880 DOI: 10.1093/nar/gkm1024] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Real-time PCR tomography is a novel, quantitative method for measuring localized RNA expression profiles within single cells. We demonstrate its usefulness by dissecting an oocyte from Xenopus laevis into slices along its animal–vegetal axis, extracting its RNA and measuring the levels of 18 selected mRNAs by real-time RT-PCR. This identified two classes of mRNA, one preferentially located towards the animal, the other towards the vegetal pole. mRNAs within each group show comparable intracellular gradients, suggesting they are produced by similar mechanisms. The polarization is substantial, though not extreme, with around 5% of vegetal gene mRNA molecules detected at the animal pole, and around 50% of the molecules in the far most vegetal section. Most animal pole mRNAs were found in the second section from the animal pole and in the central section, which is where the nucleus is located. mRNA expression profiles did not change following in vitro fertilization and we conclude that the cortical rotation that follows fertilization has no detectable effect on intracellular mRNA gradients.
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Affiliation(s)
- Radek Sindelka
- Laboratory of Gene Expression, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
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Hames RS, Hames R, Prosser SL, Euteneuer U, Lopes CAM, Moore W, Woodland HR, Fry AM. Pix1 and Pix2 are novel WD40 microtubule-associated proteins that colocalize with mitochondria in Xenopus germ plasm and centrosomes in human cells. Exp Cell Res 2007; 314:574-89. [PMID: 18068700 DOI: 10.1016/j.yexcr.2007.10.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Revised: 10/02/2007] [Accepted: 10/22/2007] [Indexed: 11/30/2022]
Abstract
In many animals, the germ line develops from a distinct mitochondria-rich region of embryonic cytoplasm called the germ plasm. However, the protein composition of germ plasm and its formation remain poorly understood, except in Drosophila. Here, we show that Xpat, a recently identified protein component of Xenopus germ plasm, interacts via its C-terminal domain with a novel protein, xPix1. Xpat and xPix1 are co-expressed in ovaries, eggs and early embryos and colocalize to the mitochondrial cloud and germ plasm in stage I and stage VI oocytes, respectively. Although Xpat appears unique to Xenopus, Pix proteins, which contain an N-terminal WD40 domain and C-terminal coiled-coil, are widely conserved. In humans, two proteins, Pix1 and Pix2, are expressed at varying levels in different cancer cell lines. Importantly, as well as localizing to mitochondria, human Pix proteins localize to centrosomes and associate with microtubules in vitro and in vivo. Although, Pix proteins are stably expressed through the cell cycle, Pix2 concentrates on microtubule structures in mitosis and microinjection of Pix antibodies interferes with cell division. Based on these data, we propose that Pix1 and Pix2 are microtubule-associated adaptor proteins that likely contribute to a range of developmental and cell division processes.
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Affiliation(s)
- Rebecca S Hames
- Department of Biochemistry, University of Leicester, University Road, Leicester LE1 9HN, UK
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11
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Heikkila JJ, Kaldis A, Morrow G, Tanguay RM. The use of the Xenopus oocyte as a model system to analyze the expression and function of eukaryotic heat shock proteins. Biotechnol Adv 2007; 25:385-95. [PMID: 17459646 DOI: 10.1016/j.biotechadv.2007.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 03/21/2007] [Accepted: 03/21/2007] [Indexed: 11/26/2022]
Abstract
The analysis of the expression and function of heat shock protein (hsp) genes, a class of molecular chaperones, has been greatly aided by studies carried out with Xenopus oocytes. The large size of the oocyte facilitates microinjection of DNA, mRNA or protein, permits manual dissection of nuclei, and allows certain assays to be performed with single oocytes. These and other characteristics were useful in identifying the cis- and trans-acting factors involved in hsp gene transcription as well as the role of chaperones and co-chaperones in the repression and activation of heat shock factor. Xenopus oocytes were used to examine heat shock protein (HSP) molecular chaperone function as well as their involvement in intracellular trafficking, maturation, and secretion of protein. Possible new areas of research with this system include the role of membranes in the heat shock response, involvement of HSPs in viral replication and maturation, and in vivo NMR spectroscopy of microinjected HSPs.
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Affiliation(s)
- John J Heikkila
- Department of Biology, University of Waterloo, Waterloo, ON, Canada N2L 3G1.
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12
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Abstract
A long-standing question in developmental biology is how amphibians establish a dorsoventral axis. The prevailing view has been that cortical rotation is used to move a dorsalizing activity from the bottom of the egg towards the future dorsal side. We review recent evidence that kinesin-dependent movement of particles containing components of the Wnt intracellular pathway contributes to the formation of the dorsal organizer, and suggest that cortical rotation functions to align and orient microtubules, thereby establishing the direction of particle transport. We propose a new model in which active particle transport and cortical rotation cooperate to generate a robust movement of dorsal determinants towards the future dorsal side of the embryo.
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Affiliation(s)
- Carole Weaver
- Department of Biochemistry, Box 357350, University of Washington, Seattle, WA 98195-7350, USA
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13
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Prodon F, Prulière G, Chenevert J, Sardet C. [Establishment and expression of embryonic axes: comparisons between different model organisms]. Med Sci (Paris) 2004; 20:526-38. [PMID: 15190470 DOI: 10.1051/medsci/2004205526] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In an accompanying article (C. Sardet et al. m/s 2004; 20 : 414-423) we reviewed determinants of polarity in early development and the mechanisms which regulate their localization and expression. Such determinants have for the moment been identified in only a few species: the insect Drosophila melanogaster, the worm Caenorhabditis elegans, the frog Xenopus laevis and the ascidians Ciona intestinalis and Holocynthia roretzi. Although oogenesis, fertilization, and cell divisions in these embryos differ considerably, with respect to early polarities certain common themes emerge, such as the importance of cortical mRNAs, the PAR polarity proteins, and reorganizations mediated by the cytoskeleton. Here we highlight similarities and differences in axis establishment between these species, describing them in a chronological order from oocyte to gastrula, and add two more classical model organisms, sea urchin and mouse, to complete the comparisons depicted in the form of a Poster which can be downloaded from the site http://biodev.obs-vlfr.fr/biomarcell.
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Affiliation(s)
- François Prodon
- BioMarCell, Laboratoire de biologie du développement, UMR 7009 CNRS-UPMC, Observatoire, Station zoologique, 06230 Villefranche-sur-Mer, France
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Sardet C, Prodon F, Prulière G, Chenevert J. Polarisation des oeufs et des embryons : principes communs. Med Sci (Paris) 2004; 20:414-23. [PMID: 15124113 DOI: 10.1051/medsci/2004204414] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Embryonic development depends on the establishment of polarities which define the axial characteristics of the body. In a small number of cases such as the embryo of the fly drosophila, developmental axes are established well before fertilization while in other organisms such as the nematode worm C. elegans these axes are set up only after fertilization. In most organisms the egg posesses a primary (A-V, Animal-Vegetal) axis acquired during oogenesis which participates in the establishment of the embryonic axes. Such is the case for the eggs of ascidians or the frog Xenopus whose AV axes are remodelled by sperm entry to yield the embryonic axes. Embryos of different species thus acquire an anterior end and a posterior end (Antero-Posterior, A-P axis), dorsal and ventral sides (D-V axis) and then a left and a right side.
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Affiliation(s)
- Christian Sardet
- BioMarCell, Laboratoire de biologie du développement, UMR 7009 CNRS-UPMC, Station zoologique, 06230 Villefranche-sur-Mer, France.
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15
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Gard DL. Confocal fluorescence microscopy of the cytoskeleton of amphibian oocytes and embryos. Methods Cell Biol 2003; 70:379-416. [PMID: 12512330 DOI: 10.1016/s0091-679x(02)70011-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- David L Gard
- Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA
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16
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Rappleye CA, Tagawa A, Lyczak R, Bowerman B, Aroian RV. The anaphase-promoting complex and separin are required for embryonic anterior-posterior axis formation. Dev Cell 2002; 2:195-206. [PMID: 11832245 DOI: 10.1016/s1534-5807(02)00114-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Polarization of the one-cell C. elegans embryo establishes the animal's anterior-posterior (a-p) axis. We have identified reduction-of-function anaphase-promoting complex (APC) mutations that eliminate a-p polarity. We also demonstrate that the APC activator cdc20 is required for polarity. The APC excludes PAR-3 from the posterior cortex, allowing PAR-2 to accumulate there. The APC is also required for tight cortical association and posterior movement of the paternal pronucleus and its associated centrosome. Depletion of the protease separin, a downstream target of the APC, causes similar pronuclear and a-p polarity defects. We propose that the APC/separin pathway promotes close association of the centrosome with the cortex, which in turn excludes PAR-3 from the posterior pole early in a-p axis formation.
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Affiliation(s)
- Chad A Rappleye
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093, USA
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17
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Nir A. The fertilization dance: a mechanical view of the egg rotation during the initial spermatozoa-ovum interaction. J Theor Biol 2002; 214:171-9. [PMID: 11812171 DOI: 10.1006/jtbi.2001.2464] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The motion of the ovum and the spermatozoa toward each other in the oviduct culminates in a meeting that ultimately results in fertilization. This encounter is characterized by a slow rotation of the sperms-egg cluster while the sperms attempt a penetration. The mysterious rotation was observed in vivo and in vitro for homologous and heterologous systems. It lacks a satisfactory biological explanation while it seems to be correlated with the efficiency of fertilization. A simple bio-mechanical model presented here predicts that the slow rotation of the sperms-egg cluster is a natural consequence of the encounter in most cases. A linear stability analysis of the system suggests a quantitative explanation of the rotation causes, its intensity and its direction. The entire encounter seems as a micro-scale process of courting of the ovum by the spermatozoa, which is expressed as circular dance.
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Affiliation(s)
- Avinoam Nir
- Department of Chemical Engineering, Technion, Haifa 32000, Israel.
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18
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Sardet C, Prodon F, Dumollard R, Chang P, Chênevert J. Structure and function of the egg cortex from oogenesis through fertilization. Dev Biol 2002; 241:1-23. [PMID: 11784091 DOI: 10.1006/dbio.2001.0474] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Christian Sardet
- BioMarCell, UMR 7009 Biologie du Developpement, Villefranche sur Mer, 06230, France.
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19
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Early embryo orientation with respect to the cardinal points in natural clutches of two ranidae species inhabiting geographically distant regions. Russ J Dev Biol 2000. [DOI: 10.1007/bf02758909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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20
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Marrari Y, Terasaki M, Arrowsmith V, Houliston E. Local inhibition of cortical rotation in Xenopus eggs by an anti-KRP antibody. Dev Biol 2000; 224:250-62. [PMID: 10926764 DOI: 10.1006/dbio.2000.9773] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The dorsal-ventral axis of amphibian embryos is specified by the "cortical rotation," a translocation of the egg cortex relative to the vegetal yolk mass. The mechanism of cortical rotation is not understood but is thought to involve an array of aligned, commonly oriented microtubules. We have demonstrated an essential requirement for kinesin-related proteins (KRPs) in the cortical rotation by microinjection beneath the vegetal cortex of an antipeptide antibody recognising multiple Xenopus egg KRPs. Time-lapse videomicroscopy revealed a striking local inhibition of the cortical rotation around the injection site, indicating that KRP-mediated translocation of the cortex is generated by forces acting across the vegetal subcortical region. Anti-tubulin immunofluorescence showed that the antibody disrupted both formation and maintenance of the aligned microtubule array. Direct examination of rhodamine-labelled microtubules by confocal microscopy showed that the anti-KRP antibody provoked striking three-dimensional flailing movement of the subcortical microtubules. In contrast, microtubules in antibody-free regions undulated only within the plane of the cortex, a significant population exhibiting little or no net movement. These findings suggest that KRPs have a critical role during cortical rotation in tethering microtubules to the cortex and that they may not contribute significantly to the translocation force as previously thought.
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Affiliation(s)
- Y Marrari
- Unité de Biologie du Développement, UMR 7009 CNRS/, Université Paris VI, Station Zoologique, Villefranche-sur-mer, France
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