scholarly journals Contact area–dependent cell communication and the morphological invariance of ascidian embryogenesis

Science ◽  
2020 ◽  
Vol 369 (6500) ◽  
pp. eaar5663 ◽  
Author(s):  
Léo Guignard ◽  
Ulla-Maj Fiúza ◽  
Bruno Leggio ◽  
Julien Laussu ◽  
Emmanuel Faure ◽  
...  
Keyword(s):  
Marine Invertebrate ◽  
Cell Communication ◽  
Light Sheet ◽  
Embryonic Cell ◽  
Cell Segmentation ◽  
Asymmetric Cell Divisions ◽  
Morphogen Gradients ◽  
Cell Lineages ◽  
Genomic Divergence ◽  
Dependent Cell

Marine invertebrate ascidians display embryonic reproducibility: Their early embryonic cell lineages are considered invariant and are conserved between distantly related species, despite rapid genomic divergence. Here, we address the drivers of this reproducibility. We used light-sheet imaging and automated cell segmentation and tracking procedures to systematically quantify the behavior of individual cells every 2 minutes during Phallusia mammillata embryogenesis. Interindividual reproducibility was observed down to the area of individual cell contacts. We found tight links between the reproducibility of embryonic geometries and asymmetric cell divisions, controlled by differential sister cell inductions. We combined modeling and experimental manipulations to show that the area of contact between signaling and responding cells is a key determinant of cell communication. Our work establishes the geometric control of embryonic inductions as an alternative to classical morphogen gradients and suggests that the range of cell signaling sets the scale at which embryonic reproducibility is observed.

scholarly journals Contact-dependent cell-cell communications drive morphological invariance during ascidian embryogenesis

2017 ◽  
Author(s):  
Léo Guignard ◽  
Ulla-Maj Fiuza ◽  
Bruno Leggio ◽  
Emmanuel Faure ◽  
Julien Laussu ◽  
...  
Keyword(s):  
Individual Cell ◽  
Inverse Correlation ◽  
Light Sheet ◽  
Embryonic Cell ◽  
Cell Behaviors ◽  
Fate Specification ◽  
Cell Lineages ◽  
Genomic Divergence ◽  
Dependent Cell ◽  
Local Cell

ABSTRACTCanalization of developmental processes ensures the reproducibility and robustness of embryogenesis within each species. In its extreme form, found in ascidians, early embryonic cell lineages are invariant between embryos within and between species, despite rapid genomic divergence. To resolve this paradox, we used live light-sheet imaging to quantify individual cell behaviors in digitalized embryos and explore the forces that canalize their development. This quantitative approach revealed that individual cell geometries and cell contacts are strongly constrained, and that these constraints are tightly linked to the control of fate specification by local cell inductions. While in vertebrates ligand concentration usually controls cell inductions, we found that this role is fulfilled in ascidians by the area of contacts between signaling and responding cells. We propose that the duality between geometric and genetic control of inductions contributes to the counterintuitive inverse correlation between geometric and genetic variability during embryogenesis.

scholarly journals Spatiotemporal sequence of mesoderm and endoderm lineage segregation during mouse gastrulation

2020 ◽  
Author(s):  
Simone Probst ◽  
Sagar ◽  
Jelena Tosic ◽  
Carsten Schwan ◽  
Dominic Grün ◽  
...  
Keyword(s):  
Mouse Embryo ◽  
Primitive Streak ◽  
Cell Types ◽  
Complete Separation ◽  
Embryonic Cell ◽  
Spatiotemporal Pattern ◽  
Cell Lineages ◽  
Dependent Cell ◽  
Summary Statement ◽  
Germ Layer Formation

AbstractAnterior mesoderm (AM) and definitive endoderm (DE) progenitors represent the earliest embryonic cell types that are specified during germ layer formation at the primitive streak (PS) of the mouse embryo. Genetic experiments indicate that both lineages segregate from Eomes expressing progenitors in response to different NODAL signaling levels. However, the precise spatiotemporal pattern of the emergence of these cell types and molecular details of lineage segregation remain unexplored. We combined genetic fate labeling and imaging approaches with scRNA-seq to follow the transcriptional identities and define lineage trajectories of Eomes dependent cell types. All cells moving through the PS during the first day of gastrulation express Eomes. AM and DE specification occurs before cells leave the PS from discrete progenitor populations that are generated in distinct spatiotemporal patterns. Importantly, we don’t find evidence for the existence of progenitors that co-express markers of both cell lineages suggesting an immediate and complete separation of AM and DE lineages.Summary statementCells lineages are specified in the mouse embryo already within the primitive streak where Mesp1+ mesoderm and Foxa2+ endoderm are generated in a spatial and temporal sequence from unbiased progenitors.

ISOLATION AND GENETIC CHARACTERIZATION OF CELL-LINEAGE MUTANTS OF THE NEMATODE CAENORHABDITIS ELEGANS

Genetics ◽  
1980 ◽  
Vol 96 (2) ◽  
pp. 435-454 ◽  
Author(s):  
H Robert Horvitz ◽  
John E Sulston
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Lineage ◽  
Embryonic Cell ◽  
Null Alleles ◽  
Recessive Mutation ◽  
Incomplete Penetrance ◽  
Nematode Caenorhabditis Elegans ◽  
Cell Lineages ◽  
Cell Divisions ◽  
Recessive Mutations

ABSTRACT Twenty-four mutants that alter the normally invariant post-embryonic cell lineages of the nematode Caenorhabditis elegans have been isolated and genetically characterized. In some of these mutants, cell divisions fail that occur in wild-type animals; in other mutants, cells divide that do not normally do so. The mutants differ in the specificities of their defects, so that it is possible to identify mutations that affect some cell lineages but not others. These mutants define 14 complementation groups, which have been mapped. The abnormal phenotype of most of the cell-lineage mutants results from a single recessive mutation; however, the excessive cell divisions characteristic of one strain, CB1322, require the presence of two unlinked recessive mutations. All 24 cell-lineage mutants display incomplete penetrance and/or variable expressivity. Three of the mutants are suppressed by pleiotropic suppressors believed to be specific for null alleles, suggesting that their phenotypes result from the complete absence of gene activity.

scholarly journals Gap Junction Dependent Cell Communication Is Modulated During Transdifferentiation of Mesenchymal Stem/Stromal Cells Towards Neuron-Like Cells

2020 ◽  
Vol 8 ◽  
Author(s):  
Nadine Dilger ◽  
Anna-Lena Neehus ◽  
Klaudia Grieger ◽  
Andrea Hoffmann ◽  
Max Menssen ◽  
...  
Keyword(s):  
Gap Junction ◽  
Stromal Cells ◽  
Cell Communication ◽  
Dependent Cell

Selective contact-dependent cell communication

Nature ◽  
1976 ◽  
Vol 264 (5588) ◽  
pp. 760-762 ◽  
Author(s):  
I. FENTIMAN ◽  
J. TAYLOR-PAPADIMITRIOU ◽  
M. STOKER
Keyword(s):  
Cell Communication ◽  
Dependent Cell

scholarly journals Imaging the dynamic recruitment of monocytes to the blood–brain barrier and specific brain regions during Toxoplasma gondii infection

2019 ◽  
Vol 116 (49) ◽  
pp. 24796-24807 ◽  
Author(s):  
Christine A. Schneider ◽  
Dario X. Figueroa Velez ◽  
Ricardo Azevedo ◽  
Evelyn M. Hoover ◽  
Cuong J. Tran ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Blood Brain Barrier ◽  
Light Sheet ◽  
Brain Regions ◽  
Brain Barrier ◽  
Cell Segmentation ◽  
Cns Infection ◽  
Light Sheet Microscopy ◽  
Blood Brain ◽  
The Brain

Brain infection by the parasite Toxoplasma gondii in mice is thought to generate vulnerability to predation by mechanisms that remain elusive. Monocytes play a key role in host defense and inflammation and are critical for controlling T. gondii. However, the dynamic and regional relationship between brain-infiltrating monocytes and parasites is unknown. We report the mobilization of inflammatory (CCR2+Ly6Chi) and patrolling (CX3CR1+Ly6Clo) monocytes into the blood and brain during T. gondii infection of C57BL/6J and CCR2RFP/+CX3CR1GFP/+ mice. Longitudinal analysis of mice using 2-photon intravital imaging of the brain through cranial windows revealed that CCR2-RFP monocytes were recruited to the blood–brain barrier (BBB) within 2 wk of T. gondii infection, exhibited distinct rolling and crawling behavior, and accumulated within the vessel lumen before entering the parenchyma. Optical clearing of intact T. gondii-infected brains using iDISCO+ and light-sheet microscopy enabled global 3D detection of monocytes. Clusters of T. gondii and individual monocytes across the brain were identified using an automated cell segmentation pipeline, and monocytes were found to be significantly correlated with sites of T. gondii clusters. Computational alignment of brains to the Allen annotated reference atlas [E. S. Lein et al., Nature 445:168–176 (2007)] indicated a consistent pattern of monocyte infiltration during T. gondii infection to the olfactory tubercle, in contrast to LPS treatment of mice, which resulted in a diffuse distribution of monocytes across multiple brain regions. These data provide insights into the dynamics of monocyte recruitment to the BBB and the highly regionalized localization of monocytes in the brain during T. gondii CNS infection.

scholarly journals Ontogenetic Survey of Histone Modifications in an Annelid

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Glenys Gibson ◽  
Corban Hart ◽  
Robyn Pierce ◽  
Vett Lloyd
Keyword(s):  
Gene Expression ◽  
Histone Modifications ◽  
Marine Invertebrates ◽  
Marine Invertebrate ◽  
Specific Cell ◽  
Early Cleavage ◽  
Cell Lineages ◽  
Common Time ◽  
Wide Range ◽  
Development And Differentiation

Histone modifications are widely recognized for their fundamental importance in regulating gene expression in embryonic development in a wide range of eukaryotes, but they have received relatively little attention in the development of marine invertebrates. We surveyed histone modifications throughout the development of a marine annelid, Polydora cornuta, to determine if modifications could be detected immunohistochemically and if there were characteristic changes in modifications throughout ontogeny (surveyed at representative stages from oocyte to adult). We found a common time of onset for three histone modifications in early cleavage (H3K14ac, H3K9me, and H3K4me2), some differences in the distribution of modifications among germ layers, differences in epifluorescence intensity in specific cell lineages suggesting that hyperacetylation (H3K14ac) and hypermethylation (H3K9me) occur during differentiation, and an overall decrease in the distribution of modifications from larvae to adults. Although preliminary, these results suggest that histone modifications are involved in activating early development and differentiation in a marine invertebrate.

scholarly journals Myosin-dependent cell-cell communication controls synchronicity of division in acute and chronic stages of Toxoplasma gondii

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Karine Frénal ◽  
Damien Jacot ◽  
Pierre-Mehdi Hammoudi ◽  
Arnault Graindorge ◽  
Bohumil Maco ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Cell Communication ◽  
Dependent Cell ◽  
Cell Cell

scholarly journals Development of a 3D atlas of the embryonic pancreas for topological and quantitative analysis of heterologous cell interactions

2021 ◽  
Author(s):  
Laura Glorieux ◽  
Aleksandra Sapala ◽  
David Willnow ◽  
Manon Moulis ◽  
Shlomit Edri ◽  
...  
Keyword(s):  
Spatial Organization ◽  
Current Knowledge ◽  
Image Data ◽  
Light Sheet ◽  
Cell Types ◽  
Pancreatic Tissue ◽  
Embryonic Cell ◽  
Cell Interactions ◽  
Distinct Cell

AbstractGenerating comprehensive image maps, while preserving spatial 3D context, is essential to quantitatively assess and locate specific cellular features and cell-cell interactions during organ development. Despite the recent advances in 3D imaging approaches, our current knowledge of the spatial organization of distinct cell types in the embryonic pancreatic tissue is still largely based on 2D histological sections. Here, we present a light-sheet fluorescence microscopy approach to image the pancreas in 3D and map tissue interactions at key development time points in the mouse embryo. We used transgenic mouse models and antibodies to visualize the three main cellular components within the developing pancreas, including epithelial, mesenchymal and endothelial cell populations. We demonstrated the utility of the approach by providing volumetric data, 3D distribution of distinct progenitor populations and quantification of relative cellular abundance within the tissue. Lastly, our image data were combined in an open source online repository (referred to as Pancreas Embryonic Cell Atlas). This image dataset will serve the scientific community by enabling further investigation on pancreas organogenesis but also for devising strategies for the in vitro generation of transplantable pancreatic tissue for regenerative therapies.

scholarly journals Generation and timing of graded responses to morphogen gradients

Development ◽  
2021 ◽  
Vol 148 (24) ◽  
Author(s):  
Shari Carmon ◽  
Felix Jonas ◽  
Naama Barkai ◽  
Eyal D. Schejter ◽  
Ben-Zion Shilo
Keyword(s):  
Gene Expression ◽  
Rna Polymerase Ii ◽  
Target Genes ◽  
Cell Formation ◽  
Embryonic Cell ◽  
Mrna Accumulation ◽  
Temporal Regulation ◽  
Morphogen Gradients ◽  
Graded Response ◽  
Spatio Temporal

ABSTRACT Morphogen gradients are known to subdivide a naive cell field into distinct zones of gene expression. Here, we examine whether morphogens can also induce a graded response within such domains. To this end, we explore the role of the Dorsal protein nuclear gradient along the dorsoventral axis in defining the graded pattern of actomyosin constriction that initiates gastrulation in early Drosophila embryos. Two complementary mechanisms for graded accumulation of mRNAs of crucial zygotic Dorsal target genes were identified. First, activation of target-gene expression expands over time from the ventral-most region of high nuclear Dorsal to lateral regions, where the levels are lower, as a result of a Dorsal-dependent activation probability of transcription sites. Thus, sites that are activated earlier will exhibit more mRNA accumulation. Second, once the sites are activated, the rate of RNA Polymerase II loading is also dependent on Dorsal levels. Morphological restrictions require that translation of the graded mRNA be delayed until completion of embryonic cell formation. Such timing is achieved by large introns, which provide a delay in production of the mature mRNAs. Spatio-temporal regulation of key zygotic genes therefore shapes the pattern of gastrulation.

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