The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Nicolas Plachta - One of the best experts on this subject based on the ideXlab platform.
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Instructions for Assembling the Early Mammalian Embryo
Developmental cell, 2018Co-Authors: Melanie D. White, Jennifer Zenker, Stephanie Bissiere, Nicolas PlachtaAbstract:The preimplantation mouse Embryo is a simple self-contained system, making it an excellent model to discover how Mammalian cells function in real time and in vivo. Work over the last decade has revealed some key morphogenetic mechanisms that drive early development, yielding rudimentary instructions for the generation of a Mammalian Embryo. Here, we review the instructions revealed thus far, and then discuss remaining challenges to discover upstream factors controlling cell fate determination, test the role of mechanisms based on biological noise, and take advantage of recent technological developments to advance the spatial and temporal resolution of our current understanding.
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How cells change shape and position in the early Mammalian Embryo
Current opinion in cell biology, 2016Co-Authors: Melanie D. White, Jennifer Zenker, Stephanie Bissiere, Nicolas PlachtaAbstract:During preimplantation development, cells of the Mammalian Embryo must resolve their shape and position to ensure the future viability of the fetus. These initial changes are established as the Embryo expands from one to thirty-two cells, and a group of originally spherical cells is transformed into a more polarized structure with distinct cell geometries and lineages. Recent advances in the application of non-invasive imaging technologies have enabled the discovery of mechanisms regulating patterning of the early Mammalian Embryo. Here, we review recent findings revealing cell protrusions that trigger early changes in cell shape and Embryo compaction, and how anisotropies in mechanical forces drive the first spatial segregation of cells in the Embryo to form the pluripotent inner mass.
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cortical tension allocates the first inner cells of the Mammalian Embryo
Developmental Cell, 2015Co-Authors: Chaminda R Samarage, Melanie D. White, Stephanie Bissiere, Yanina D. Álvarez, Juan Carlos Fierrogonzalez, Yann Nicholas Henon, Edwin Chitran Jesudason, Andreas Fouras, Nicolas PlachtaAbstract:Every cell in our body originates from the pluripotent inner mass of the Embryo, yet it is unknown how biomechanical forces allocate inner cells in vivo. Here we discover subcellular heterogeneities in tensile forces, generated by actomyosin cortical networks, which drive apical constriction to position the first inner cells of living mouse Embryos. Myosin II accumulates specifically around constricting cells, and its disruption dysregulates constriction and cell fate. Laser ablations of actomyosin networks reveal that constricting cells have higher cortical tension, generate tension anisotropies and morphological changes in adjacent regions of neighboring cells, and require their neighbors to coordinate their own changes in shape. Thus, tensile forces determine the first spatial segregation of cells during Mammalian development. We propose that, unlike more cohesive tissues, the early Embryo dissipates tensile forces required by constricting cells via their neighbors, thereby allowing confined cell repositioning without jeopardizing global architecture.
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How Adhesion Forms the Early Mammalian Embryo
Current topics in developmental biology, 2015Co-Authors: Melanie D. White, Nicolas PlachtaAbstract:The early mouse Embryo is an excellent system to study how a small group of initially rounded cells start to change shape and establish the first forms of adhesion-based cell-cell interactions in mammals in vivo. In addition to its critical role in the structural integrity of the Embryo, we discuss here how adhesion is important to regulate cell polarity and cell fate. Recent evidence suggests that adherens junctions participate in signaling pathways by localizing key proteins to subcellular microdomains. E-cadherin has been identified as the main player required for the establishment of adhesion but other mechanisms involving additional proteins or physical forces acting in the Embryo may also contribute. Application of new technologies that enable high-resolution quantitative imaging of adhesion protein dynamics and measurements of biomechanical forces will provide a greater understanding of how adhesion patterns the early Mammalian Embryo.
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oct4 kinetics predict cell lineage patterning in the early Mammalian Embryo
Nature Cell Biology, 2011Co-Authors: Nicolas Plachta, Tobias Bollenbach, Shirley Pease, Scott E. Fraser, Periklis PantazisAbstract:Transcription factors are central to sustaining pluripotency, yet little is known about transcription factor dynamics in defining pluripotency in the early Mammalian Embryo. Here, we establish a fluorescence decay after photoactivation (FDAP) assay to quantitatively study the kinetic behaviour of Oct4, a key transcription factor controlling pre-implantation development in the mouse Embryo. FDAP measurements reveal that each cell in a developing Embryo shows one of two distinct Oct4 kinetics, before there are any morphologically distinguishable differences or outward signs of lineage patterning. The differences revealed by FDAP are due to differences in the accessibility of Oct4 to its DNA binding sites in the nucleus. Lineage tracing of the cells in the two distinct sub-populations demonstrates that the Oct4 kinetics predict lineages of the early Embryo. Cells with slower Oct4 kinetics are more likely to give rise to the pluripotent cell lineage that contributes to the inner cell mass. Those with faster Oct4 kinetics contribute mostly to the extra-Embryonic lineage. Our findings identify Oct4 kinetics, rather than differences in total transcription factor expression levels, as a predictive measure of developmental cell lineage patterning in the early mouse Embryo.
Periklis Pantazis - One of the best experts on this subject based on the ideXlab platform.
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symmetry breaking in the early Mammalian Embryo the case for quantitative single cell imaging analysis
Molecular Human Reproduction, 2016Co-Authors: Maaike Welling, Aaron Ponti, Periklis PantazisAbstract:In recent years, advances in imaging probes, cutting-edge microscopy techniques and powerful bioinformatics image analysis have markedly expanded the imaging toolbox available to developmental biologists. Apart from traditional qualitative studies, Embryonic development can now be investigated in vivo with improved spatiotemporal resolution, with more detailed quantitative analyses down to the single-cell level of the developing Embryo. Such imaging tools can provide many benefits to investigate the emergence of the asymmetry in the early Mammalian Embryo. Quantitative single-cell imaging has provided a deeper knowledge of the dynamic processes of how and why apparently indistinguishable cells adopt separate fates that ensure proper lineage allocation and segregation. To advance our understanding of the mechanisms governing such cell fate decisions, we will need to address current limitations of fluorescent probes, while at the same time take on challenges in image processing and analysis. New discoveries and developments in quantitative, single-cell imaging analysis will ultimately enable a truly comprehensive, multi-dimensional and multi-scale investigation of the dynamic morphogenetic processes that work in concert to shape the Embryo.
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transcription factor kinetics and the emerging asymmetry in the early Mammalian Embryo
Cell Cycle, 2012Co-Authors: Periklis Pantazis, Tobias BollenbachAbstract:There is a long-running controversy about how early cell fate decisions are made in the developing Mammalian Embryo.1,2 In particular, it is controversial when the first events that can predict the establishment of the pluripotent and extra-Embryonic lineages in the blastocyst of the pre-implantation Embryo occur. It has long been proposed that the position and polarity of cells at the 16- to 32-cell stage Embryo influence their decision to either give rise to the pluripotent cell lineage that eventually contributes to the inner cell mass (ICM), comprising the primitive endoderm (PE) and the epiblast (EPI), or the extra-Embryonic trophectoderm (TE) surrounding the blastocoel. The positioning of cells in the Embryo at this developmental stage could largely be the result of random events, making this a stochastic model of cell lineage allocation. Contrary to such a stochastic model, some studies have detected putative differences in the lineage potential of individual blastomeres before compaction, indicati...
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oct4 kinetics predict cell lineage patterning in the early Mammalian Embryo
Nature Cell Biology, 2011Co-Authors: Nicolas Plachta, Tobias Bollenbach, Shirley Pease, Scott E. Fraser, Periklis PantazisAbstract:Transcription factors are central to sustaining pluripotency, yet little is known about transcription factor dynamics in defining pluripotency in the early Mammalian Embryo. Here, we establish a fluorescence decay after photoactivation (FDAP) assay to quantitatively study the kinetic behaviour of Oct4, a key transcription factor controlling pre-implantation development in the mouse Embryo. FDAP measurements reveal that each cell in a developing Embryo shows one of two distinct Oct4 kinetics, before there are any morphologically distinguishable differences or outward signs of lineage patterning. The differences revealed by FDAP are due to differences in the accessibility of Oct4 to its DNA binding sites in the nucleus. Lineage tracing of the cells in the two distinct sub-populations demonstrates that the Oct4 kinetics predict lineages of the early Embryo. Cells with slower Oct4 kinetics are more likely to give rise to the pluripotent cell lineage that contributes to the inner cell mass. Those with faster Oct4 kinetics contribute mostly to the extra-Embryonic lineage. Our findings identify Oct4 kinetics, rather than differences in total transcription factor expression levels, as a predictive measure of developmental cell lineage patterning in the early mouse Embryo.
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Oct4 kinetics predict cell lineage patterning in the early Mammalian Embryo
Nature Cell Biology, 2011Co-Authors: Nicolas Plachta, Tobias Bollenbach, Shirley Pease, Scott E. Fraser, Periklis PantazisAbstract:Transcription factors are central to sustaining pluripotency, yet little is known about transcription factor dynamics in defining pluripotency in the early Mammalian Embryo. Here, we establish a fluorescence decay after photoactivation (FDAP) assay to quantitatively study the kinetic behaviour of Oct4, a key transcription factor controlling pre-implantation development in the mouse Embryo. FDAP measurements reveal that each cell in a developing Embryo shows one of two distinct Oct4 kinetics, before there are any morphologically distinguishable differences or outward signs of lineage patterning. The differences revealed by FDAP are due to differences in the accessibility of Oct4 to its DNA binding sites in the nucleus. Lineage tracing of the cells in the two distinct sub-populations demonstrates that the Oct4 kinetics predict lineages of the early Embryo. Cells with slower Oct4 kinetics are more likely to give rise to the pluripotent cell lineage that contributes to the inner cell mass. Those with faster Oct4 kinetics contribute mostly to the extra-Embryonic lineage. Our findings identify Oct4 kinetics, rather than differences in total transcription factor expression levels, as a predictive measure of developmental cell lineage patterning in the early mouse Embryo. Very little is known about the role of transcription factors DNA-binding dynamics in defining development and pluriotency. Cells in the early mouse Embryo display two classes of Oct4 kinetics that define two subpopulations of cells with distinct lineage potential.
Magdalena Zernicka-goetz - One of the best experts on this subject based on the ideXlab platform.
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Principles of Self-Organization of the Mammalian Embryo.
Cell, 2020Co-Authors: Meng Zhu, Magdalena Zernicka-goetzAbstract:Early Embryogenesis is a conserved and self-organized process. In the Mammalian Embryo, the potential for self-organization is manifested in its extraordinary developmental plasticity, allowing a correctly patterned Embryo to arise despite experimental perturbation. The underlying mechanisms enabling such regulative development have long been a topic of study. In this Review, we summarize our current understanding of the self-organizing principles behind the regulative nature of the early Mammalian Embryo. We argue that geometrical constraints, feedback between mechanical and biochemical factors, and cellular heterogeneity are all required to ensure the developmental plasticity of Mammalian Embryo development.
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Deconstructing and reconstructing the mouse and human early Embryo
Nature Cell Biology, 2018Co-Authors: Marta N. Shahbazi, Magdalena Zernicka-goetzAbstract:Shahbazi et al. review our current understanding of the post-implantation Mammalian Embryo and how innovative technologies have helped to shape it. The emergence of form and function during Mammalian Embryogenesis is a complex process that involves multiple regulatory levels. The foundations of the body plan are laid throughout the first days of post-implantation development as Embryonic stem cells undergo symmetry breaking and initiate lineage specification, in a process that coincides with a global morphological reorganization of the Embryo. Here, we review experimental models and how they have shaped our current understanding of the post-implantation Mammalian Embryo.
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Tracing the origin of heterogeneity and symmetry breaking in the early Mammalian Embryo.
Nature communications, 2018Co-Authors: Qi Chen, Junchao Shi, Yi Tao, Magdalena Zernicka-goetzAbstract:A fundamental question in developmental and stem cell biology concerns the origin and nature of signals that initiate asymmetry leading to pattern formation and self-organization. Instead of having prominent pre-patterning determinants as present in model organisms (worms, sea urchin, frog), we propose that the Mammalian Embryo takes advantage of more subtle cues such as compartmentalized intracellular reactions that generate micro-scale inhomogeneity, which is gradually amplified over several cellular generations to drive pattern formation while keeping developmental plasticity. It is therefore possible that by making use of compartmentalized information followed by its amplification, Mammalian Embryos would follow general principle of development found in other organisms in which the spatial cue is more robustly presented.
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Rhythmic actomyosin-driven contractions induced by sperm entry predict Mammalian Embryo viability
Nature Communications, 2011Co-Authors: Anna Ajduk, Tagbo Ilozue, Shane Windsor, Yuansong Yu, K. Bianka Seres, Richard J. Bomphrey, Karl Swann, Adrian Thomas, Chris Graham, Magdalena Zernicka-goetzAbstract:Cytoplasmic flows—the movement of cytoplasmic material—can be detected following the fertilization of an egg by a sperm in many species. In this study, rhythmic cytoplasmic flows are shown to be induced in mice by calcium-induced cytoskeleton contractions which could be used to predict the successful outcome of fertilization. Fertilization-induced cytoplasmic flows are a conserved feature of eggs in many species. However, until now the importance of cytoplasmic flows for the development of Mammalian Embryos has been unknown. Here, by combining a rapid imaging of the freshly fertilized mouse egg with advanced image analysis based on particle image velocimetry, we show that fertilization induces rhythmical cytoplasmic movements that coincide with pulsations of the protrusion forming above the sperm head. We find that these movements are caused by contractions of the actomyosin cytoskeleton triggered by Ca^2+ oscillations induced by fertilization. Most importantly, the relationship between the movements and the events of egg activation makes it possible to use the movements alone to predict developmental potential of the zygote. In conclusion, this method offers, thus far, the earliest and fastest, non-invasive way to predict the viability of eggs fertilized in vitro and therefore can potentially improve greatly the prospects for IVF treatment.
Tobias Bollenbach - One of the best experts on this subject based on the ideXlab platform.
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transcription factor kinetics and the emerging asymmetry in the early Mammalian Embryo
Cell Cycle, 2012Co-Authors: Periklis Pantazis, Tobias BollenbachAbstract:There is a long-running controversy about how early cell fate decisions are made in the developing Mammalian Embryo.1,2 In particular, it is controversial when the first events that can predict the establishment of the pluripotent and extra-Embryonic lineages in the blastocyst of the pre-implantation Embryo occur. It has long been proposed that the position and polarity of cells at the 16- to 32-cell stage Embryo influence their decision to either give rise to the pluripotent cell lineage that eventually contributes to the inner cell mass (ICM), comprising the primitive endoderm (PE) and the epiblast (EPI), or the extra-Embryonic trophectoderm (TE) surrounding the blastocoel. The positioning of cells in the Embryo at this developmental stage could largely be the result of random events, making this a stochastic model of cell lineage allocation. Contrary to such a stochastic model, some studies have detected putative differences in the lineage potential of individual blastomeres before compaction, indicati...
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oct4 kinetics predict cell lineage patterning in the early Mammalian Embryo
Nature Cell Biology, 2011Co-Authors: Nicolas Plachta, Tobias Bollenbach, Shirley Pease, Scott E. Fraser, Periklis PantazisAbstract:Transcription factors are central to sustaining pluripotency, yet little is known about transcription factor dynamics in defining pluripotency in the early Mammalian Embryo. Here, we establish a fluorescence decay after photoactivation (FDAP) assay to quantitatively study the kinetic behaviour of Oct4, a key transcription factor controlling pre-implantation development in the mouse Embryo. FDAP measurements reveal that each cell in a developing Embryo shows one of two distinct Oct4 kinetics, before there are any morphologically distinguishable differences or outward signs of lineage patterning. The differences revealed by FDAP are due to differences in the accessibility of Oct4 to its DNA binding sites in the nucleus. Lineage tracing of the cells in the two distinct sub-populations demonstrates that the Oct4 kinetics predict lineages of the early Embryo. Cells with slower Oct4 kinetics are more likely to give rise to the pluripotent cell lineage that contributes to the inner cell mass. Those with faster Oct4 kinetics contribute mostly to the extra-Embryonic lineage. Our findings identify Oct4 kinetics, rather than differences in total transcription factor expression levels, as a predictive measure of developmental cell lineage patterning in the early mouse Embryo.
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Oct4 kinetics predict cell lineage patterning in the early Mammalian Embryo
Nature Cell Biology, 2011Co-Authors: Nicolas Plachta, Tobias Bollenbach, Shirley Pease, Scott E. Fraser, Periklis PantazisAbstract:Transcription factors are central to sustaining pluripotency, yet little is known about transcription factor dynamics in defining pluripotency in the early Mammalian Embryo. Here, we establish a fluorescence decay after photoactivation (FDAP) assay to quantitatively study the kinetic behaviour of Oct4, a key transcription factor controlling pre-implantation development in the mouse Embryo. FDAP measurements reveal that each cell in a developing Embryo shows one of two distinct Oct4 kinetics, before there are any morphologically distinguishable differences or outward signs of lineage patterning. The differences revealed by FDAP are due to differences in the accessibility of Oct4 to its DNA binding sites in the nucleus. Lineage tracing of the cells in the two distinct sub-populations demonstrates that the Oct4 kinetics predict lineages of the early Embryo. Cells with slower Oct4 kinetics are more likely to give rise to the pluripotent cell lineage that contributes to the inner cell mass. Those with faster Oct4 kinetics contribute mostly to the extra-Embryonic lineage. Our findings identify Oct4 kinetics, rather than differences in total transcription factor expression levels, as a predictive measure of developmental cell lineage patterning in the early mouse Embryo. Very little is known about the role of transcription factors DNA-binding dynamics in defining development and pluriotency. Cells in the early mouse Embryo display two classes of Oct4 kinetics that define two subpopulations of cells with distinct lineage potential.
F. Bargy - One of the best experts on this subject based on the ideXlab platform.
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surgical approach of an early Mammalian Embryo the rabbit model
Fetal Diagnosis and Therapy, 1998Co-Authors: Sylvie Beaudoin, J Simeoni, P Sacquin, L. Simon, F. BargyAbstract:We describe an experimental surgical model in early rabbit Embryo (12.5 days of gestation). Twenty-one Embryos were operated, of which 9 survived the first postoperative week and 5 had normal further
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Surgical Approach of an Early Mammalian Embryo: The Rabbit Model
Fetal diagnosis and therapy, 1998Co-Authors: Sylvie Beaudoin, J Simeoni, P Sacquin, L. Simon, F. BargyAbstract:We describe an experimental surgical model in early rabbit Embryo (12.5 days of gestation). Twenty-one Embryos were operated, of which 9 survived the first postoperative week and 5 had normal further growth until term. As far as we can ascertain, this is the first successful report of a surgical approach in early Mammalian Embryos. We think that this model may be useful for workers involved in the study of early congenital malformations.
