scholarly journals Mechanics of human embryo compaction

2022 ◽  
Author(s):  
Julie Firmin ◽  
Nicolas Ecker ◽  
Diane Rivet Danon ◽  
Virginie Barraud Lange ◽  
Herve Turlier ◽  
...  
Keyword(s):  
Human Embryo ◽  
Close Contact ◽  
Fold Increase ◽  
Human Embryos ◽  
Cell Contractility ◽  
Cellular Processes ◽  
Physical Mechanisms ◽  
Evolutionarily Conserved ◽  
Cell Medium ◽  
Cell Cell

The shaping of the human embryo begins with compaction, during which cells come into close contact and form a tighter structure. Assisted reproductive technology (ART) studies suggest that human embryos fail compaction primarily because of defective adhesion. Based on our current understanding of animal morphogenesis, other morphogenetic engines, such as cell contractility, could be involved in shaping the human embryo. However, the molecular, cellular and physical mechanisms driving human embryo morphogenesis remain uncharacterized. Using micropipette aspiration on human embryos donated to research, we have mapped cell surface tensions during compaction. This reveals a 4-fold increase of tension at the cell-medium interface while cell-cell contacts keep a steady tension. Comparison between human and mouse reveals qualitatively similar but quantitively different mechanical strategies, with human embryos being mechanically least efficient. Inhibition of cell contractility and cell-cell adhesion in human embryos reveal that only contractility controls the surface tension responsible for compaction. Interestingly, if both cellular processes are required for compaction, they exhibit distinct mechanical signatures when faulty. Analyzing the mechanical signature of naturally failing embryos, we find evidence that non-compacting embryos or partially compacting embryos with excluded cells have defective contractility. Together, our study reveals that an evolutionarily conserved increase in cell contractility is required to generate the forces driving the first morphogenetic movement shaping the human body.

scholarly journals Stick around: Cell–Cell Adhesion Molecules during Neocortical Development

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 118
Author(s):  
David de Agustín-Durán ◽  
Isabel Mateos-White ◽  
Jaime Fabra-Beser ◽  
Cristina Gil-Sanz
Keyword(s):  
Cell Adhesion ◽  
Adhesion Molecules ◽  
Cell Adhesion Molecules ◽  
Neural Cells ◽  
Surface Receptors ◽  
Cellular Processes ◽  
Neocortical Development ◽  
Classical Cadherins ◽  
Adhesive Interactions ◽  
Cell Cell

The neocortex is an exquisitely organized structure achieved through complex cellular processes from the generation of neural cells to their integration into cortical circuits after complex migration processes. During this long journey, neural cells need to establish and release adhesive interactions through cell surface receptors known as cell adhesion molecules (CAMs). Several types of CAMs have been described regulating different aspects of neurodevelopment. Whereas some of them mediate interactions with the extracellular matrix, others allow contact with additional cells. In this review, we will focus on the role of two important families of cell–cell adhesion molecules (C-CAMs), classical cadherins and nectins, as well as in their effectors, in the control of fundamental processes related with corticogenesis, with special attention in the cooperative actions among the two families of C-CAMs.

scholarly journals Modelling Nuclear Morphology and Shape Transformation: A Review

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 540
Author(s):  
Chao Fang ◽  
Jiaxing Yao ◽  
Xingyu Xia ◽  
Yuan Lin
Keyword(s):  
Shape Change ◽  
Boundary Integral ◽  
Shape Transformation ◽  
Cellular Processes ◽  
Physical Mechanisms ◽  
Intracellular Forces ◽  
Cellular Compartments ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome ◽  
Made In

As one of the most important cellular compartments, the nucleus contains genetic materials and separates them from the cytoplasm with the nuclear envelope (NE), a thin membrane that is susceptible to deformations caused by intracellular forces. Interestingly, accumulating evidence has also indicated that the morphology change of NE is tightly related to nuclear mechanotransduction and the pathogenesis of diseases such as cancer and Hutchinson–Gilford Progeria Syndrome. Theoretically, with the help of well-designed experiments, significant progress has been made in understanding the physical mechanisms behind nuclear shape transformation in different cellular processes as well as its biological implications. Here, we review different continuum-level (i.e., energy minimization, boundary integral and finite element-based) approaches that have been developed to predict the morphology and shape change of the cell nucleus. Essential gradients, relative advantages and limitations of each model will be discussed in detail, with the hope of sparking a greater research interest in this important topic in the future.

scholarly journals Modulation of Cell–Cell Interactions in Drosophila Oocyte Development

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 274
Author(s):  
Matthew Antel ◽  
Mayu Inaba
Keyword(s):  
Cell Communication ◽  
Cell Interaction ◽  
Oocyte Development ◽  
Suitable Model ◽  
Physiological Regulation ◽  
Temporal Regulation ◽  
Cellular Processes ◽  
Cellular Machinery ◽  
Drosophila Ovary ◽  
Cell Cell

The Drosophila ovary offers a suitable model system to study the mechanisms that orchestrate diverse cellular processes. Oogenesis starts from asymmetric stem cell division, proper differentiation and the production of fully patterned oocytes equipped with all the maternal information required for embryogenesis. Spatial and temporal regulation of cell-cell interaction is particularly important to fulfill accurate biological outcomes at each step of oocyte development. Progress has been made in understanding diverse cell physiological regulation of signaling. Here we review the roles of specialized cellular machinery in cell-cell communication in different stages of oogenesis.

scholarly journals Coupling between apical tension and basal adhesion allow epithelia to collectively sense and respond to substrate topography over long distances

2015 ◽  
Vol 7 (12) ◽  
pp. 1611-1621 ◽  
Author(s):  
Kyle E. Broaders ◽  
Alec E. Cerchiari ◽  
Zev J. Gartner
Keyword(s):  
Substrate Topography ◽  
Cell Substrate ◽  
Sense And Respond ◽  
Cell Medium ◽  
Cell Cell

Epithelia have the capacity to sense and respond to substrate topography through the coupling of tensions at the cell–cell, cell–substrate, and cell–medium interfaces.

Spinal cord-notochord relationship in normal human embryos and in a human embryo with double spinal cord

1993 ◽  
Vol 86 (5) ◽  
Author(s):  
Mirna Saraga-Babi� ◽  
Vedran Stefanovi� ◽  
Jorma Wartiovaara ◽  
Eero Lehtonen
Keyword(s):  
Spinal Cord ◽  
Human Embryo ◽  
Human Embryos ◽  
Normal Human

scholarly journals Chromatin architectural proteins regulate flowering time by precluding gene looping

2021 ◽  
Vol 7 (24) ◽  
pp. eabg3097
Author(s):  
Bo Zhao ◽  
Yanpeng Xi ◽  
Junghyun Kim ◽  
Sibum Sung
Keyword(s):  
Chromatin Structure ◽  
Cellular Processes ◽  
Genome Wide ◽  
A Genome ◽  
Evolutionarily Conserved ◽  
Architectural Proteins ◽  
Floral Repressor ◽  
Flanking Regions ◽  
Genome Wide Study

Chromatin structure is critical for gene expression and many other cellular processes. In Arabidopsis thaliana, the floral repressor FLC adopts a self-loop chromatin structure via bridging of its flanking regions. This local gene loop is necessary for active FLC expression. However, the molecular mechanism underlying the formation of this class of gene loops is unknown. Here, we report the characterization of a group of linker histone-like proteins, named the GH1-HMGA family in Arabidopsis, which act as chromatin architecture modulators. We demonstrate that these family members redundantly promote the floral transition through the repression of FLC. A genome-wide study revealed that this family preferentially binds to the 5′ and 3′ ends of gene bodies. The loss of this binding increases FLC expression by stabilizing the FLC 5′ to 3′ gene looping. Our study provides mechanistic insights into how a family of evolutionarily conserved proteins regulates the formation of local gene loops.

scholarly journals Developmentally regulated GTPases: structure, function and roles in disease

2021 ◽  
Author(s):  
Christian A. E. Westrip ◽  
Qinqin Zhuang ◽  
Charlotte Hall ◽  
Charlotte D. Eaton ◽  
Mathew L. Coleman
Keyword(s):  
Cell Proliferation ◽  
Structural Biology ◽  
Regulatory Protein ◽  
Growth Control ◽  
Developmentally Regulated ◽  
Binding Partner ◽  
Cellular Processes ◽  
Gtp Binding ◽  
Evolutionarily Conserved ◽  
Cell Growth Control

AbstractGTPases are a large superfamily of evolutionarily conserved proteins involved in a variety of fundamental cellular processes. The developmentally regulated GTP-binding protein (DRG) subfamily of GTPases consists of two highly conserved paralogs, DRG1 and DRG2, both of which have been implicated in the regulation of cell proliferation, translation and microtubules. Furthermore, DRG1 and 2 proteins both have a conserved binding partner, DRG family regulatory protein 1 and 2 (DFRP1 and DFRP2), respectively, that prevents them from being degraded. Similar to DRGs, the DFRP proteins have also been studied in the context of cell growth control and translation. Despite these proteins having been implicated in several fundamental cellular processes they remain relatively poorly characterized, however. In this review, we provide an overview of the structural biology and biochemistry of DRG GTPases and discuss current understanding of DRGs and DFRPs in normal physiology, as well as their emerging roles in diseases such as cancer.

La fine del concetto di “pre-embrione” nella Convenzione di Oviedo / The end of the concept of “pre-embryo” in the Oviedo Convention

2018 ◽  
Vol 66 (6) ◽  
pp. 735-745
Author(s):  
Carlo Casini ◽  
Marina Casini
Keyword(s):  
Human Embryo ◽  
Legal Status ◽  
Human Embryos ◽  
Specific Reference ◽  
Constitutional Court ◽  
The European Union ◽  
Council Of Europe ◽  
European Court ◽  
The Moment

Il contributo si sofferma sulla questione riguardante la ricerca scientifica sugli embrioni generati in vitro. L’articolo 18 della Convenzione riguarda specificamente la sperimentazione sull’embrione in vitro e per questo esso è sottoposto ad una riflessione particolarmente approfondita. L’obiettivo è quello di capire se dalla Convenzione emergono linee idonee a definire lo statuto giuridico dell’embrione umano. Gli Autori concludono nel senso che nonostante il concetto di pre-embrione (formulato proprio per teorizzare l’insignificanza dell’embrione umano nei primi 14 giorni dalla fecondazione) sia stato accolto in alcune leggi e abbia implicitamente guidato l’interpretazione di alcuni aspetti relativi alla valutazione del valore dell’embrione, la Convenzione di bioetica lo ha definitivamente respinto con il massimo di autorevolezza. La conclusione è raggiunta attraverso l’esame dell’art. 18 considerandone anche la precedente formulazione contenuta in una bozza; mediante una interpretazione sistematica della Convenzione che esige il riconoscimento del concepito, fin dalla fecondazione, come un “essere umano”; esaminando i contributi preparatori elaborati dalla Assemblea Parlamentare del Consiglio d’Europa e del Parlamento Europeo; prendendo in considerazione gli sviluppi della Convenzione di Oviedo con specifico riferimento al tema del pre-embrione. L’indagine si avvale poi anche di ampi riferimenti alla giurisprudenza della Corte europea dei diritti dell’uomo del Consiglio d’Europa, alla giurisprudenza della Corte di Giustizia dell’Unione Europea, ad alcune recenti decisioni della Corte Costituzionale italiana. ---------- The paper focuses on the question concerning scientific research on human embryos generated in vitro. Article 18 of the Oviedo Convention specifically concerns the experimentation on the in vitro embryos and for this reason it is subject to a particularly in-depth reflection. The goal is to understand if the Convention shows suitable lines to define the legal status of the human embryo. The authors conclude that despite the concept of pre-embryo (formulated to theorize the insignificance of the human embryo in the first 14 days of fertilization) has been accepted in some laws and has implicitly guided the interpretation of some aspects related to the evaluation of the value of the embryo, the Bioethics Convention definitively rejected it with the utmost authority. The conclusion is reached through the examination of the art. 18 also considering the previous formulation contained in a draft; through a systematic interpretation of the Convention which requires the recognition of the conceived, from the moment of fertilization, as a “human being”; examining the preparatory contributions prepared by the Parliamentary Assembly of the Council of Europe and the European Parliament; taking into consideration the developments of the Oviedo Convention with specific reference to the theme of the pre-embryo. The investigation also makes use of extensive references to the jurisprudence of the European Court of Human Rights of the Council of Europe, to the jurisprudence of the Court of Justice of the European Union, to some recent decisions of the Italian Constitutional Court.

Sachstand zur Manipulierbarkeit des menschlichen Embryos hinsichtlich seiner Spezieszugehörigkeit und Entwicklungsfähigkeit

2020 ◽  
Vol 28 (1) ◽  
pp. 5-12
Author(s):  
Martin Hähnel ◽  
Roland Kipke
Keyword(s):  
Human Embryo ◽  
Legal Status ◽  
Human Embryos ◽  
Current State ◽  
Embryo Protection Act ◽  
Species Membership ◽  
State Of Research

This report presents the current state of research in the debate on embryo protection. On the basis of scientific findings on species membership and the capacity of human embryos to develop properly, the report examines the extent to which these empirical facts influence the debate on the legal status of the human embryo. At the end of the article, the authors present the options for the further discussion with regard to the German Embryo Protection Act.

scholarly journals Crystal structure of yeast Sis1 peptide-binding fragment and Hsp70 Ssa1 C-terminal complex

2006 ◽  
Vol 398 (3) ◽  
pp. 353-360 ◽  
Author(s):  
Jingzhi Li ◽  
Yunkun Wu ◽  
Xinguo Qian ◽  
Bingdong Sha
Keyword(s):  
Crystal Structure ◽  
Close Contact ◽  
Critical Role ◽  
Peptide Binding ◽  
Structural Basis ◽  
Cellular Processes ◽  
Terminal Form ◽  
Charged Residues ◽  
Domain I

Heat shock protein (Hsp) 40 facilitates the critical role of Hsp70 in a number of cellular processes such as protein folding, assembly, degradation and translocation in vivo. Hsp40 and Hsp70 stay in close contact to achieve these diverse functions. The conserved C-terminal EEVD motif in Hsp70 has been shown to regulate Hsp40–Hsp70 interaction by an unknown mechanism. Here, we provide a structural basis for this regulation by determining the crystal structure of yeast Hsp40 Sis1 peptide-binding fragment complexed with the Hsp70 Ssa1 C-terminal. The Ssa1 extreme C-terminal eight residues, G634PTVEEVD641, form a β-strand with the domain I of Sis1 peptide-binding fragment. Surprisingly, the Ssa1 C-terminal binds Sis1 at the site where Sis1 interacts with the non-native polypeptides. The negatively charged residues within the EEVD motif in Ssa1 C-terminal form extensive charge–charge interactions with the positively charged residues in Sis1. The structure-based mutagenesis data support the structural observations.

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