The cell surface of the mammalian embryo during early development

1984 ◽  
pp. 190-204 ◽  
Author(s):  
Lynn M. Wiley
Keyword(s):  
Cell Surface ◽  
Early Development ◽  
Mammalian Embryo

scholarly journals Two independent forms of endocytosis maintain embryonic cell surface homeostasis during early development

2008 ◽  
Vol 316 (1) ◽  
pp. 135-148 ◽  
Author(s):  
J. Fernando Covian-Nares ◽  
Robert M. Smith ◽  
Steven S. Vogel
Keyword(s):  
Cell Surface ◽  
Early Development ◽  
Embryonic Cell

Change in Surface Extensibility of Fundulus Deep Cells During Early Development

1973 ◽  
Vol 13 (3) ◽  
pp. 721-726
Author(s):  
CHERYLL A. TICKLE ◽  
J. P. TRINKAUS
Keyword(s):  
Cell Surface ◽  
Early Development ◽  
Negative Pressure ◽  
Stages Of Development ◽  
Rounded Form ◽  
Early Gastrula

The extensibility of the periphery of the deep cells of the Fundulus blastoderm was investigated by applying negative pressure to the cell surface in culture by means of a micropipette. The relative negative pressure required to produce standard deformations of the surface was measured for cells from embryos in 2 different stages of development. Less negative pressure was required to deform cells from early gastrulae than cells from early blastulae. This finding correlates with the behaviour of deep cells in vivo: early blastula cells are rounded, form blebs, and do not engage in locomotion, whereas early gastrula cells form extended lobopodia and lamellipodia and engage actively in locomotion.

scholarly journals Eomesodermin is functionally conserved between zebrafish and mouse in spite of different mutant phenotypic severities, and controls left/right organiser formation via interlocking feedforward loops

2020 ◽  
Author(s):  
Conor D. Talbot ◽  
Mark D. Walsh ◽  
Stephen J. Cutty ◽  
Randa Elsayed ◽  
Ashley E. E. Bruce ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Early Development ◽  
Functional Divergence ◽  
Cell Lineage ◽  
Early Embryo ◽  
Molecular Function ◽  
Molecular Configuration ◽  
Mammalian Embryo ◽  
T Box ◽  
Functional Capabilities

AbstractThe T-box family transcription factor Eomesodermin (Eomes) is present in all vertebrates, with many key roles in the developing mammalian embryo and immune system. Homozygous Eomes mutant mouse embryos exhibit early lethality due to defects in both the embryonic mesendoderm and the extraembryonic trophoblast cell lineage. In contrast, zebrafish lacking the predominant Eomes homologue A (Eomesa) do not suffer complete lethality and can be maintained. This suggests fundamental differences in either the molecular function of Eomes orthologues or the molecular configuration of processes in which they participate. To explore these hypotheses we initially analysed the expression of distinct Eomes isoforms in various cell mouse types. Next we compared the functional capabilities of these murine isoforms compared to zebrafish Eomesa. These experiments provided no evidence for functional divergence. Next we examined the functions of zebrafish Eomesa and other T-box family members expressed in early development, as well as its paralogue Eomesb. Though Eomes is a member of the Tbr1 subfamily we found strong evidence for functional redundancy without complete functional equivalence with the Tbx6 subfamily member Tbx16, known to be absent from eutherians and other mammals. Finally, we analysed the ability of Eomesa to induce zebrafish left-right organiser progenitors (known as dorsal forerunner cells) known to be positively regulated by vgll4l, a gene we had previously shown to be repressed by Eomesa. Here we demonstrate that Eomesa indirectly upregulates vgll4l expression via interlocking feedforward loops, suggesting a role in establishment of left/right asymmetry. Overall these findings demonstrate conservation of Eomes molecular function and participation in similar processes, but differential requirements across evolution due to the expanded complement of T-box factors in teleosts. Our analyses also provide insights into the role of Eomesa in left-right organiser formation in zebrafish.Author summaryRecent studies provide evidence for both shared and unique molecular pathways controlling early development in different vertebrate organisms. The transcription factor Eomesodermin plays essential roles during mammalian development and has potent functional capabilities in zebrafish embryos yet is seemingly dispensable for viability. Here we compared functional contributions of the predominant zebrafish Eomesodermin homologue - Eomesa - with multiple isoforms of mouse Eomesodermin. We found them to be functionally indistinguishable in the early embryo. Surprisingly, a distant relative of Eomesodermin in the zebrafish embryo – Tbx16 – which is absent in mammals shows a degree of functional overlap with Eomesodermin, underscoring the different evolutionary requirements for Eomesodermin in teleosts and mammals. Finally, we demonstrate that Eomesodermin differentially regulates the transcriptional cofactor vgll4l, which plays key roles in formation of the zebrafish left/right organiser, at different stages of development. Thus, our work demonstrates the molecular function of Eomesodermin is likely to be conserved throughout vertebrate evolution despite differences in mutant phenotypes, and reveals regulatory mechanisms controlling left/right asymmetric patterning.

scholarly journals Epithelial-Mesenchymal Transition Drives Three-Dimensional Morphogenesis in Mammalian Early Development

2021 ◽  
Vol 9 ◽  
Author(s):  
Galym Ismagulov ◽  
Sofiane Hamidi ◽  
Guojun Sheng
Keyword(s):  
Early Development ◽  
Epithelial Mesenchymal Transition ◽  
Three Dimensional ◽  
Early Embryo ◽  
Dynamic Changes ◽  
Mammalian Embryo ◽  
Mesenchymal Transition ◽  
Cellular Morphogenesis ◽  
Biomechanical Force ◽  
Mesenchymal Epithelial Transition

From fertilization to onset of gastrulation, a mammalian embryo goes through several rounds of cellular morphogenesis resembling phenomena of epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET), collectively referred to as EMTs. How these EMT events play a role in shaping the three-dimensional (3-D) architecture of the developing embryo is not well-understood. In this review, we present a model in which cellular morphogenesis, represented primarily by dynamic changes in its epithelialization status, is the driving force of embryonic 3-D organization. This is achieved through the integration of three key components of mammalian early development, the pluripotency regulation, morphogenetic signaling, and biomechanical force anisotropy. Although cells in an early embryo do not exhibit full mesenchymal characteristics, our model underscores the importance of investigating molecular regulation of epithelial cell polarity and partial EMT/MET in understanding mammalian early development.

scholarly journals An activated Ras protein alters cell adhesion by dephosphorylating Dictyostelium DdCAD-1

Microbiology ◽  
2006 ◽  
Vol 152 (5) ◽  
pp. 1497-1505 ◽  
Author(s):  
David M. Secko ◽  
Chi-Hung Siu ◽  
George B. Spiegelman ◽  
Gerald Weeks
Keyword(s):  
Signal Transduction ◽  
Cell Adhesion ◽  
Cell Surface ◽  
Early Development ◽  
Cell Adhesion Molecule ◽  
Null Cell ◽  
Phosphorylation State ◽  
Ras Protein ◽  
Molecular Components ◽  
Null Strain

RasG-regulated signal transduction has been linked to a variety of growth-specific processes and appears to also play a role in the early development of Dictyostelium discoideum. In an attempt to uncover some of the molecular components involved in Ras-mediated signalling, several proteins have been described previously, including the cell adhesion molecule DdCAD-1, whose phosphorylation state was affected by the expression of the constitutively activated RasG, RasG(G12T). Here it has been shown that a cadA null strain lacks the phosphoproteins that were tentatively identified as DdCAD-1, confirming its previous designation. Further investigation revealed that cells expressing RasG(G12T) exhibited increased cell–cell cohesion, concomitant with reduced levels of DdCAD-1 phosphorylation. This increased cohesion was DdCAD-1-dependent and was correlated with increased localization of DdCAD-1 at the cell surface. DdCAD-1 phosphorylation was also found to decrease during Dictyostelium aggregation. These results revealed a possible role for protein phosphorylation in regulating DdCAD-1-mediated cell adhesion during early development. In addition, the levels of DdCAD-1 protein were substantially reduced in a rasG null cell line. These results indicate that RasG affects both the expression and dephosphorylation of DdCAD-1 during early development.

Individual differences, social attention, and the history of the social motivation hypotheses of autism

2019 ◽  
Vol 42 ◽  
Author(s):  
Peter C. Mundy
Keyword(s):  
Individual Differences ◽  
Early Development ◽  
Emotional Development ◽  
Social Motivation ◽  
Social Attention ◽  
Social Emotional Development ◽  
Social Emotional ◽  
Precise Understanding ◽  
The Social ◽  
History Of

Abstract The stereotype of people with autism as unresponsive or uninterested in other people was prominent in the 1980s. However, this view of autism has steadily given way to recognition of important individual differences in the social-emotional development of affected people and a more precise understanding of the possible role social motivation has in their early development.

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