Search results for "Gastrulation"
showing 10 items of 27 documents
Axis Specification in Zebrafish Is Robust to Cell Mixing and Reveals a Regulation of Pattern Formation by Morphogenesis
2020
Summary A fundamental question in developmental biology is how the early embryo establishes the spatial coordinate system that is later important for the organization of the embryonic body plan. Although we know a lot about the signaling and gene-regulatory networks required for this process, much less is understood about how these can operate to pattern tissues in the context of the extensive cell movements that drive gastrulation. In zebrafish, germ layer specification depends on the inheritance of maternal mRNAs [1, 2, 3], cortical rotation to generate a dorsal pole of β-catenin activity [4, 5, 6, 7, 8], and the release of Nodal signals from the yolk syncytial layer (YSL) [9, 10, 11, 12]…
2018
During gastrulation, embryonic cells become specified into distinct germ layers. In mouse, this continues throughout somitogenesis from a population of bipotent stem cells called neuromesodermal progenitors (NMps). However, the degree of self-renewal associated with NMps in the fast-developing zebrafish embryo is unclear. With a genetic clone tracing method, we labelled early embryonic progenitors and find a strong clonal similarity between spinal cord and mesoderm tissues. We followed individual cell lineages by light-sheet imaging, revealing a common neuromesodermal lineage contribution to a subset of spinal cord tissue across the anterior-posterior body axis. An initial population subdiv…
Self-organised symmetry breaking in zebrafish reveals feedback from morphogenesis to pattern formation
2019
A fundamental question in developmental biology is how the early embryo breaks initial symmetry to establish the spatial coordinate system later important for the organisation of the embryonic body plan. In zebrafish, this is thought to depend on the inheritance of maternal mRNAs [1–3], cortical rotation to generate a dorsal pole of beta-catenin activity [4–8] and the release of Nodal signals from the yolk syncytial layer (YSL) [9–12]. Recent work aggregating mouse embryonic stem cells has shown that symmetry breaking can occur in the absence of extra-embryonic tissue [19,20]. To test whether this is also true in zebrafish, we separated embryonic cells from the yolk and allowed them to deve…
Correction
2019
ABSTRACT During gastrulation, embryonic cells become specified into distinct germ layers. In mouse, this continues throughout somitogenesis from a population of bipotent stem cells called neuromesodermal progenitors (NMps). However, the degree of self-renewal associated with NMps in the fast-developing zebrafish embryo is unclear. Using a genetic clone-tracing method, we labelled early embryonic progenitors and found a strong clonal similarity between spinal cord and mesoderm tissues. We followed individual cell lineages using light-sheet imaging, revealing a common neuromesodermal lineage contribution to a subset of spinal cord tissue across the anterior-posterior body axis. An initial pop…
Neuromesodermal Progenitors are a Conserved Source of Spinal Cord with Divergent Growth Dynamics
2018
AbstractDuring gastrulation, embryonic cells become specified into distinct germ layers. In mouse, this continues throughout somitogenesis from a population of bipotent stem cells called neuromesodermal progenitors (NMps). However, the degree self-renewal is associated with NMps in the fast-developing zebrafish embryo is unclear. With a genetic clone tracing method, we labelled early embryonic progenitors and find a strong clonal similarity between spinal cord and mesoderm tissues. We then followed individual cell lineages by light-sheet imaging and reveal a common neuromesodermal lineage contribution to a subset of spinal cord tissue across the anterior-posterior body axis. An initial popu…
The dynamics of structural modifications of mitochondria at the early stages of sea urchin embryonic development
1992
The organization of the chondriome and the ultrastructure of mitochondria have been studied in eggs and embryos of the sea urchin Paracentrotus lividus. The egg chondriome is characterized by an arrangement in well-delimited clusters. Analysis of mitochondrial clusters on electron micrographs of ultrathin serial sections shows two kinds of mitochondria of different shapes, the rod-shaped and the spherical. The egg mitochondria have a dense matrix and a well-ordered arrangement of cristae which, in rod-shaped variety, are perpendicular to the major axis. Cell division is accompanied by significant changes in intracellular distribution of mitochondria and in their structure. At the stage of 2…
The origin of postembryonic neuroblasts in the ventral nerve cord of Drosophila melanogaster.
1991
ABSTRACT Embryonic and postembryonic neuroblasts in the thoracic ventral nerve cord of Drosophila melanogaster have the same origin. We have traced the development of threefold-labelled single precursor cells from the early gastrula stage to late larval stages. The technique allows in the same individual monitoring of progeny cells at embryonic stages (in vivo) and differentially staining embryonic and postembryonic progeny within the resulting neural clone at late postembryonic stages. The analysis reveals that postembryonic cells always appear together with embryonic cells in one clone. Further-more, BrdU labelling suggests that the embryonic neuroblast itself rather than one of its proge…
cis-Regulatory sequences driving the expression of the Hbox12 homeobox-containing gene in the presumptive aboral ectoderm territory of the Paracentro…
2008
AbstractEmbryonic development is coordinated by networks of evolutionary conserved regulatory genes encoding transcription factors and components of cell signalling pathways. In the sea urchin embryo, a number of genes encoding transcription factors display territorial restricted expression. Among these, the zygotic Hbox12 homeobox gene is transiently transcribed in a limited number of cells of the animal-lateral half of the early Paracentrotus lividus embryo, whose descendants will constitute part of the ectoderm territory. To obtain insights on the regulation of Hbox12 expression, we have explored the cis-regulatory apparatus of the gene. In this paper, we show that the intergenic region …
In vivo fate mapping with SCL regulatory elements identifies progenitors for primitive and definitive hematopoiesis in mice.
2009
10 páginas, 6 figuras.-- et al.
La distribuzione dell'attività proteasica nella blastula e nella giovane gastrula diDiscoglossus pictus
1956
Summary Protease activity has been measured in the animal and vegetal half of the blastula and in the dorsal and ventral regions of the early gastrula of Discoglossus pictus. A higher protease activity was found in the dorsal region of the early gastrula, where presumptive chordamesoderm and presumptive neuroectoderm are localized.