Search results for "Ectoderm"
showing 10 items of 100 documents
Single cell cultures of Drosophila neuroectodermal and mesectodermal central nervous system progenitors reveal different degrees of developmental aut…
2009
Abstract Background The Drosophila embryonic central nervous system (CNS) develops from two sets of progenitor cells, neuroblasts and ventral midline progenitors, which behave differently in many respects. Neuroblasts derive from the neurogenic region of the ectoderm and form the lateral parts of the CNS. Ventral midline precursors are formed by two rows of mesectodermal cells and build the CNS midline. There is plenty of evidence that individual identities are conferred to precursor cells by positional information in the ectoderm. It is unclear, however, how far the precursors can maintain their identities and developmental properties in the absence of normal external signals. Results To s…
Differential effects of EGF receptor signalling on neuroblast lineages along the dorsoventral axis of the Drosophila CNS
1998
ABSTRACT The Drosophila ventral nerve cord derives from a stereotype population of about 30 neural stem cells, the neuroblasts, per hemineuromere. Previous experiments provided indications for inductive signals at ventral sites of the neuroectoderm that confer neuroblast identities. Using cell lineage analysis, molecular markers and cell transplantation, we show here that EGF receptor signalling plays an instructive role in CNS patterning and exerts differential effects on dorsoventral subpopulations of neuroblasts. The Drosophila EGF receptor (DER) is capable of cell autonomously specifiying medial and intermediate neuroblast cell fates. DER signalling appears to be most critical for prope…
Stage-specific inductive signals in the Drosophila neuroectoderm control the temporal sequence of neuroblast specification.
2001
One of the initial steps of neurogenesis in the Drosophila embryo is the delamination of a stereotype set of neural progenitor cells (neuroblasts) from the neuroectoderm. The time window of neuroblast segregation has been divided into five successive waves (S1-S5) in which subsets of neuroblasts with specific identities are formed. To test when identity specification of the various neuroblasts takes place and whether extrinsic signals are involved, we have performed heterochronic transplantation experiments. Single neuroectodermal cells from stage 10 donor embryos (after S2) were transplanted into the neuroectoderm of host embryos at stage 7 (before S1) and vice versa. The fate of these cel…
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 …
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.
Prosthetic rehabilitation of a young patient affected by Ectodermal Dysplasia with the new Eclipse Resin System
2012
Ectodermal dysplasia is a genetic disease caused by incorrect development of the epidermis and cutaneous adnexa (for example hair, nails and sweat glands). It is often associated with skeletal and dental development anomalies. The main clinical manifestations of these syndromes are hypotrichosis, hypohydrosis and hypodontia or anodontia. Polymethyl methacrylate (PMMA) is still the most frequently used material in denture bases, but it can lead to irritation, inflammation and allergic reactions in the oral mucosa, due to the release of residual monomers. This clinical report describes a case of Hypohydrotic Ectodermal Dysplasia, rehabilitated with removable dentures made with a new monomer-f…
A novel EDA variant causing X-linked hypohidrotic ectodermal dysplasia: Case report
2021
Abstract Hereditary ectodermal dysplasias are a complex group of inherited disorders characterised by abnormalities in two or more ectodermal derivatives (skin, nails, sweat glands, etc.). There are two main types of these disorders – hidrotic and hypohidrotic/anhidrotic ectodermal dysplasias. Hypohidrotic ectodermal dysplasia (HED) or Christ-Siemens-Touraine syndrome (OMIM: 305100 ) occurs in 1 out of 5000–10,000 births [19] and has an X-linked recessive inheritance pattern (X-linked hypohydrotic ectodermal dysplasia – XLHED) [2] . The main cause of XLHED is a broad range of pathogenic variants in the EDA gene (HGNC:3157, Xq12-13) which encodes the transmembrane protein ectodysplasin-A [4]…
Hypohidrotic Ectodermal Dysplasia with total anodontia: A case report
2011
Ectodermal dysplasia is a hereditary disorder that occurs as a consequence of disturbances in the ectoderm of the developing embryo. The triad of nail dystrophy, alopecia or hypotrichosis and palmoplantar hyperkeratosis is usually accompanied by a lack of sweat glands and a partial or complete absence of primary and/ or permanent dentition. A case report illustrating the prosthetic rehabilitation of a seven year old boy with hypohidrotic ectodermal dysplasia associated with total anodontia is presented.
Dental implants in patients with oral mucosal alterations : an update
2010
Objective: To determine whether a series of diseases of the oral mucosa - Sjogren syndrome, ectodermal dysplasia, epidermolysis bullosa and lichen planus - reduce the survival rate of dental implants. Material and Method: A Medline search was carried out using the key words: "Sjogren syndrome", "ectodermal dysplasia", "epidermolysis bullosa", "lichen planus" and "dental implants", including those publications involving clinical series comprising more than one patient with the mentioned disorders and treated with dental implants, in the last 10 years. Results: The study included three articles involving patients with Sjogren syndrome subjected to dental implant treatment, representing a tota…
Early asymmetric cues triggering the dorsal/ventral gene regulatory network of the sea urchin embryo
2014
Dorsal/ventral (DV) patterning of the sea urchin embryo relies on a ventrally-localized organizer expressing Nodal, a pivotal regulator of the DV gene regulatory network. However, the inceptive mechanisms imposing the symmetry-breaking are incompletely understood. In Paracentrotus lividus, the Hbox12 homeodomain-containing repressor is expressed by prospective dorsal cells, spatially facing and preceding the onset of nodal transcription. We report that Hbox12 misexpression provokes DV abnormalities, attenuating nodal and nodal-dependent transcription. Reciprocally, impairing hbox12 function disrupts DV polarity by allowing ectopic expression of nodal. Clonal loss-of-function, inflicted by b…