By means of SEM we have examined spreading and adhesive behavior of cells isolated from superficial and deep regions of germ layers from blastula to late gastrula in Rana pipiens embryos. Each of the cell populations sampled show adhesive and spreading characteristics distinctive for each region and stage which we interpret as demonstrating the following: (1) From blastula through late gastrula, cells from each region have already acquired the ability to express surface morphologic and adhesive features independently of their association with their neighbors, i.e. autonomously. (2) The distinctive spreading and adhesive characteristics for each tissue sub-population suggest kinetic properties seemingly related to their in vivo morphogenetic movements, epiboly or invagination. (3) The appearance within germ layers of two subpopulations between blastula to mid-gastrula, suggests early intratissue inductive interactions. (4) The outermost, superficial cells from each germ layer show proximal and distal surface differences which may reflect adhesive differentials as postulated by Steinberg (1970) for presumptive ectoderm cells. (5) With the exception of superficial cell proximal and distal differentiation, freshly disaggregated cells do not show morphologic characteristics seen in corresponding cells spreading for one hour.
Download full-text PDF |
Source |
|---|
Publication Analysis
Top Keywords
Similar Publications
Nup107 contributes to the maternal to zygotic transition by preventing the premature nuclear export of pri-miRNA 427.
Development
January 2025
Pediatric Genomics Discovery Program, Departments of Pediatrics and Genetics, Yale School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA.
Emerging evidence suggests that the nuclear pore complex can have unique compositions and distinct nucleoporin functions in different cells. Here, we show that Nup107, a key component of the NPC scaffold, varies in expression over development: it is expressed at higher levels in the blastula compared to the gastrula suggesting a critical role prior to gastrulation. We find depletion of Nup107 affects the differentiation of the early germ layers leading to an expansion of the ectoderm at the expense of endoderm and mesoderm.
View Article and Find Full Text PDFTissue mechanics modulate morphogen signalling to induce the head organiser.
Cells Dev
December 2024
Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK; Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile. Electronic address:
Morphogenetic movements and specification of germ layers during gastrulation are key processes that establish the vertebrate body plan. Despite substantial research into the role of tissue mechanics during gastrulation and detailed characterisation of the molecular signalling networks controlling fate determination, the interplay of mechanical cues and biochemical signals during fate specification is poorly understood. Morphogens that activate Activin/Nodal/Smad2 signalling play a key role in mesoderm induction and axial patterning.
View Article and Find Full Text PDFEarly autonomous patterning of the anteroposterior axis in gastruloids.
Development
November 2024
EMBL Barcelona, 08003 Barcelona, Spain.
Minimal in vitro systems composed of embryonic stem cells (ESCs) have been shown to recapitulate the establishment of the anteroposterior (AP) axis. In contrast to the native embryo, ESC aggregates - such as gastruloids - can break symmetry, which is demarcated by polarization of the mesodermal marker T, autonomously without any localized external cues. However, associated earliest patterning events, such as the spatial restriction of cell fates and concomitant transcriptional changes, remain poorly understood.
View Article and Find Full Text PDFMaternal and zygotic contributions to H3K4me1 chromatin marking during germ layer formation.
Dev Biol
February 2025
Developmental and Cell Biology, University of California, Irvine, CA, USA; Center for Complex Biological Systems, University of California, Irvine, CA, USA. Electronic address:
An early step in triploblastic embryo differentiation is the formation of the three germ layers. Maternal pioneer transcription factors (TFs) bind to embryonic enhancers before zygotic genome activation, initiating germ layer specification. While maternal TFs' role in establishing epigenetic marks is known, how early pluripotent cells gain spatially restricted epigenetic identities remains unclear.
View Article and Find Full Text PDFA comprehensive human embryo reference tool using single-cell RNA-sequencing data.
Nat Methods
November 2024
Department of Clinical Science, Intervention and Technology, Karolinska Institutet, and Division of Obstetrics and Gynecology, Karolinska Universitetssjukhuset, Stockholm, Sweden.
Article Synopsis
- - Stem cell-based embryo models are essential for studying early human development, but their effectiveness depends on how closely they mimic real embryos at the molecular, cellular, and structural levels.
- - Researchers created a comprehensive reference dataset by integrating six existing datasets that track human development from the zygote stage to the gastrula stage, providing a benchmark for comparing human embryo models.
- - Using an advanced analysis method called stabilized Uniform Manifold Approximation and Projection, the new reference helps identify cell types in various embryo models, revealing potential misannotations without proper reference comparisons.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!