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At least 523 records · Page 29Linked to original sources
PubMed1997

Oral-aboral ectoderm differentiation of sea urchin embryos is disrupted in response to calcium ionophore.

Intracellular signaling mediated by calcium ions has been implicated as important in controlling cell activity. The ability of calcium ionophore (A23187), which causes an increase in calcium ion concentration in the cytoplasm, to alter the pattern of differentiation of cells during sea urchin development was examined. The addition of A23187 to embryos for 3 h during early cleavage causes dramatic changes in their development during gastrulation. Using tissue-specific cDNA probes and antibodies, it was shown that A23187 causes the disruption of oral-aboral ectoderm differentiation of sea urchin embryos. The critical period for A23187 to disturb the oral-aboral ectoderm differentiation is during the cleavage stage, and treatment of embryos with A23187 after that time has little effect. The A23187 does not affect the formation of the three germ layers. These results indicate that intracellular signals mediated by calcium ions may play a key role in establishment of the oral-aboral axis during sea urchin development.

Animals↗
PubMed1998

Patterns of gene expression in the core of Spemann's organizer and activin-treated ectoderm in Cynops pyrrhogaster.

The presumptive pharyngeal endoderm region of the Cynops early gastrula induces head or trunk-tail structures in sandwich culture. Activin-treated ectoderm can mimic this phenomenon at least at the histological level. The patterns of expression of organizer-specific genes were examined to compare these two inductive materials at the molecular level. A chordin cDNA clone from Cynops pyrrhogaster (Cychd) was isolated by reverse transcription-polymerase chain reaction (RT-PCR). Cychd mRNA was first detected in the presumptive pharyngeal endoderm and prechordal plate regions of stage 11 embryos, and was expressed continuously until stage 20. The spatiotemporal expression pattern of Cychd was similar to that of Xenopus chordin. The patterns of expression of organizer-related genes in the pharyngeal endoderm and activin-treated ectoderm were compared by RT-PCR analysis. Expression of Cychd in these two materials peaked at the time when they can induce head structures in sandwich culture. Expression of fork head and goosecoid did not change in the presumptive pharyngeal endoderm over this period. Cychd may play a key role in head formation in the Cynops embryo.

Activins↗
PubMed1998

Regulation of ectodermal differentiation in Xenopus laevis animal caps treated with TPA and ammonium chloride.

Animal caps isolated from Xenopus laevis embryos at the blastula stage were treated sequentially with NH4Cl, a known cement gland inducer, and with 12-O-tetradecanoyl phorbol-13-acetate (TPA), a known neural inducer. The two artificial inducers were also used in reverse order to see if they can mimic the natural inducers acting during the progressive determination of the ectodermal organ. Immunofluorescence and whole-mount in situ hybridization were used to study the expression of tubulin, taken to indicate an early step on the pathway of cell elongation, and neural cell adhesion molecule (N-CAM) taken to indicate an early step in the determination of the nervous system. The expression of XCG-1, a marker of early specification of the cement gland, was also studied. The results showed that the two artificial inducers can mimic the effects of the natural inducers in animal cap explants. The TPA behaves like a neural inducer, reducing the number and the extension of the cement gland when added to the medium in addition to NH4Cl, before or after NH4Cl treatment. In the process of cement gland/neural induction, it is possible to redirect the ectoderm already specified as cement gland to neural tissue, but it does not seem possible to respecify the neural tissue as cement gland. Moreover, the animal caps were also cut into dorsal and ventral parts and the two halves were treated separately. The results were similar to those obtained with treatment of the entire animal cap, suggesting that a dorsal-ventral pattern is not yet established before the gastrula stage, and that in normal embryos there are boundaries between the effects of different inducers.

Ammonium Chloride↗
PubMed2001

Comparative study of sequential expression of the organizer-related genes in normal Cynops pyrrhogaster embryos and mesodermalized ectoderm.

An artificially mesodermalized ectoderm (mE) of early Cynops pyrrhogaster gastrula acquires the organizer property; the mE is able to induce the secondary axis. The expression of organizer-related genes was investigated during the mesodermalizing process of the mE. The expression of C. pyrrhogaster organizer-related genes, such as bra, gsc, lim-1, chd and noggin, were analyzed. Cynops pyrrhogaster shh expression was also investigated. The organizer-related genes were activated by 12 h after the mesoderm-inducing stimulus. It was noted that there was a temporal gap in the expression of each gene. The expression of bra and gsc seemed to be more quickly activated during the mesodermalizing process. While expression of lim-1 and noggin was activated later than that of bra and gsc, lim-1 expression was earlier than chd and noggin expression. Shh expression was activated later than lim-1/noggin. The present study suggests the possibility that the bra/gsc, lim-1, chd, noggin and shh genes are expressed one by one in that order during the mesodermalizing of the presumptive ectoderm. It also indicates that the sequence is not always consistent with that of the whole embryo during normal embryogenesis. The meaning of the discrepancy will be discussed in connection with the cascade of certain genes expressed during the mesodermalizing process.

Actins↗
PubMed2002

In the multiheaded strain (mh-1) of Hydra magnipapillata the ectodermal epithelial cells are responsible for the formation of additional heads and the endodermal epithelial cells for the reduced ability to regenerate a foot.

Hydra consist of three self-renewing cell lineages: the ectodermal epithelial, endodermal epithelial and interstitial cell lineages. The role of these cell lineages in head formation and foot regeneration in Hydra magnipapillata was studied by comparing the multiheaded strain mh-1 with the wild-type. Adult polyps of this strain show a reduced ability to regenerate a foot in the apical body half several days before additional heads are formed there. Cell lineage chimeras were produced, and it was found that in mh-1, the ectodermal epithelial cell lineage is responsible for the formation of additional heads, whereas the endodermal epithelial cell lineage and, to a lesser extent, the derivatives of the interstitial cell lineage, are responsible for the reduced ability of foot regeneration.

Animals↗
PubMedDate not supplied

AEC syndrome and CHAND syndrome: further evidence of clinical overlapping in the ectodermal dysplasias.

Among the ectodermal dysplasias, there are several examples of overlapping phenotypes in disorders that are considered distinct. We report a 5-year-old boy born to nonconsanguineous parents and presenting with ectodermal dysplasia, ankyloblepharon filiforme adnatum, and bilateral choanal atresia consistent with the diagnosis of AEC syndrome. We compare the findings in our patient with the previous reported cases and discuss the overlapping phenotype of this disorder with CHAND syndrome.

Child, Preschool↗
PubMedDate not supplied

Ectrodactyly-ectodermal dysplasia-clefting syndrome (EEC): report of a case with perioral papillomatosis.

We report a 13-year-old boy with ectodermal dysplasia, ectrodactyly, and syndactyly, hypospadias, photophobia, conductive hearing loss, and perioral papillomatosis. His father had ectrodactyly and hypotrichosis. The clinical picture suggested ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome. The presence of perioral papillomatosis, classically seen in Goltz syndrome, has been reported only once before in EEC syndrome.

Abnormalities, Multiple↗
PubMedDate not supplied

The ectrodactyly-ectodermal dysplasia-clefting syndrome (EEC): report of five cases.

We report five patients from two different pedigrees with the ectrodactyly-ectodermal dysplasia-clefting syndrome (EEC). All had features of ectodermal dysplasia, but only three had limb ectrodactyly and orofacial clefting. The present patients illustrate the great phenotypic variability in the EEC syndrome. As no single feature, including any of the three cardinal signs, is mandatory for syndrome diagnosis, a meticulous examination of all family members is needed.

Abnormalities, Multiple↗
PubMed1987

[Ocular involvement in ectodermal dysplasia].

The authors describe the ophthalmological findings and clinical course in two patients with EEC syndrome and one patient with anhydrotic ectodermal dysplasia. A retinal complication was seen in a 43-year-old patient which seems to be associated with the EEC syndrome and has not yet been described. A review of the literature indicates the frequency of ocular findings. So far, primary ocular changes in anhydrotic ectodermal dysplasia have never been observed. The older the patient, the more severe the secondary complications affecting the lids and cornea can be; the eye may even be lost.

Adult↗
PubMed1992

Extramedullary hematopoiesis of the cranial dura and anhidrotic ectodermal dysplasia.

A 2-year-old amerasian male with anhidrotic ectodermal dysplasia (Christ-Siemens-Touraine Syndrome) was admitted for status epilepticus and Mycobacteria avium-intracellulare infection. A computed tomography scan of the head revealed a mass thought to be a subdural hematoma. The patient died following overwhelming Mycobacteria avium-intracellular and Pseudomonas aeruginosa sepsis. Autopsy revealed extensive extramedullary hematopoiesis of the dura forming a tumor-like thickening with focal subdural hemorrhage. To our knowledge, this is the first report of extramedullary hematopoiesis of the cranial dura associated with anhidrotic ectodermal dysplasia.

Agammaglobulinemia↗
PubMed2001

Overlay removable partial dentures for a patient with ectodermal dysplasia: a clinical report.

The orofacial characteristics of ectodermal dysplasia include anodontia or hypodontia, hypoplastic conical teeth, underdevelopment of the alveolar ridges, frontal bossing, a depressed nasal bridge, protuberant lips, and hypotrichosis. Patients with this disease often need complex prosthetic treatment. The options for a definitive treatment plan may include fixed, removable, or implant-supported prostheses, singly or in combination. However, financial constraints and other priorities can prevent patients from choosing the most desirable treatment. This clinical report describes the diagnosis and treatment of ectodermal dysplasia in an 18-year-old man. The treatment included interim removable partial dentures fabricated to establish an acceptable therapeutic occlusal vertical dimension, followed by definitive overlay removable partial dentures and composite restorations.

Adolescent↗
PubMed2002

TRAF6-deficient mice display hypohidrotic ectodermal dysplasia.

Tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6) is an adapter protein that links signals from members of the TNFR superfamily and Toll/IL-1 receptor family to activation of transcription factors NFkappaB and AP-1. Analysis of TRAF6-deficient mice revealed that TRAF6 is essential for normal bone formation and establishment of immune and inflammatory systems. Here we report that TRAF6 deficiency results in defective development of epidermal appendixes, including guard hair follicles, sweat glands, sebaceous glands of back skin, and modified sebaceous glands such as meibomian glands, anal glands, and preputial glands. Except the sebaceous gland impairment, these abnormal phenotypes are identical to those observed in Tabby (Ta), downless (dl), and crinkled (cr) mice, which are models of hypohidrotic (anhidrotic) ectodermal dysplasia in human. beta-catenin and mucosal addressin cell adhesion molecule-1, an early marker of developing guard-hair follicles is absent in the skin of TRAF6-deficient embryos. Thus, TRAF6 is essential for development of epidermal appendixes. TRAF6 does not associate with the cytoplasmic tail of the dl protein (DL)/ectodysplasin receptor (EDAR) receptor, which, when mutated, results in hypohidrotic (anhidrotic) ectodermal dysplasia. However, TRAF6 associates with X-linked ectodysplasin-A2 receptor (XEDAR) and TNFR super family expressed on the mouse embryo (TROY/toxicity and JNK inducer (TAJ), which are EDAR-related members of the TNFR superfamily that are expressed at high level in epidermal appendixes. Furthermore, TRAF6 is essential for the XEDAR-mediated NFkappaB activation. Our results suggest that TRAF6 may transduce signals emanating from XEDAR or TROY/TAJ that are associated with development of epidermal appendixes.

Animals↗
PubMed1995

Shark, a Src homology 2, ankyrin repeat, tyrosine kinase, is expressed on the apical surfaces of ectodermal epithelia.

Tyrosine kinases, ankyrin repeats, and Src homology 2 domains play central roles in developmental processes. The cloning of a cDNA for Shark, a single protein that possesses all three domains, is described. During Drosophila embryogenesis, Shark is expressed exclusively by ectodermally derived epithelia and is localized preferentially to the apical surface of these cells. This apical localization persists, even as tissues undergo complex invaginations, moving from the external surface of embryos to form internal structures, but expression is lost when cells lose their polarity. This pattern closely mimics the expression of Crumbs, a protein necessary for proper organization of ectodermal epithelia. Shark's structure and localization pattern suggest that it functions in a signaling pathway for epithelial cell polarity, possibly transducing the Crumbs signal.

Amino Acid Sequence↗
PubMed1996

Fibroblast growth factor 2 can replace ectodermal signaling for feather development.

The initiation and morphogenesis of cutaneous appendages depend on a series of reciprocal signaling events between the epithelium and mesenchyme of the embryonic skin. In the development of feather germs, early dermal signals induce the formation of epidermal placodes that in turn signal the mesoderm to form dermal condensations immediately beneath them. We find a spatially and temporally restricted pattern of transcription for the genes that encode fibroblast growth factor (FGF) 2 and FGF receptor (FGFR) 1 in developing feather germs of the chicken embryo. FGF-2 expression is restricted to the epidermal placodes, whereas FGFR-1 expression is limited to the dermal condensations. Transcription of these genes could not be detected in skins of scaleless (sc/sc) embryos that fail to develop feathers as a result of an ectodermal defect. Treatment of sc/sc skins with FGF-2 results in the formation of feathers at the site of application of the growth factor and the induced feathers express FGFR-1 in their dermal condensations. Thus, we have established FGF-2 as an epidermal signal in early feather germ formation. The observation that FGF-2 can rescue the mutant phenotype of sc/sc embryos suggests that FGF-2 either is, or is downstream from, the signal that the sc/sc mutant ectoderm fails to generate.

Animals↗
PubMed2005

Compound heterozygosity for new splice site mutations in the plakophilin 1 gene (PKP1) in a Chinese case of ectodermal dysplasia-skin fragility syndrome.

Ectodermal dysplasia-skin fragility syndrome is a rare autosomal recessive inherited disease characterized by skin fragility, nail dystrophy and hyperkeratosis of palms and soles. Skin biopsy shows the loss of cell adhesion and the decrease of desmosomes in number and size. Mutations in PKP1 have been found to be the underlying cause of the syndrome. We report here a Chinese case of ectodermal dysplasia-skin fragility syndrome. Mutation analysis revealed compound heterozygosity for mutations in PKP1 of the proband. A new splice site mutation (c.1053 T>A+c.1054+1 G>T) near the 3' end of exon 5 and at the donor end of intron 5 on one allele was transmitted from the proband's mother. Another new splice site mutation (c.1835-2 A>G) near the acceptor end of intron 10 originated from her father. The absence of the mutant mRNA and plakophilin 1 protein in the proband's skin may result from the mechanism of nonsense-mediated mRNA decay induced by premature stop codons in PKP1 transcripts due to the two splice site mutations.

Child, Preschool↗
PubMed2000

Structural hair shaft abnormalities in hypomelanosis of ito and other ectodermal dysplasias.

Hair samples from patients with different ectodermal dysplasias; hypohidrotic ectodermal dysplasia, pachyonychia congenita, tricho-dento-osseous syndrome, tricho-rhino-phalangeal syndrome, and hypomelanosis of Ito were investigated using a scanning electron microscope. The hairs of the patients showed different structural abnormalities; twisted hairs, longitudinal grooves, trichorrhexis nodosa as well as variations in the hair caliber. Hair shaft abnormalities, as in our patients with tricho-dento-osseous syndrome, and hypomelanosis of Ito have so far not been described.

Child, Preschool↗
PubMed1970

Nucleated sites for the assembly of cytoplasmic microtubules in the ectodermal cells of blastulae of Arbacia punctulata.

In the ectodermal cells of sea urchin blastulae, the microtubules converge and appear to make contact with three distinct cytoplasmic foci or satellites associated with the basal body of the cilium. Beneath the nucleus, which lies in the apical end of the cell, the microtubules are aligned predominantly parallel to the cell's long axis and could thus make contact with the satellites as is directly suggested by observations on sections at or near the planes of the satellites. After the embryos are treated with low temperature (0 degrees C), the microtubules disassemble; however, the satellites can still be recognized. Upon rewarming, the microtubules reappear. In early stages of reformation, when the tubules in the cell consist of short segments, tubules have only been found in the apical part of the cell. One end of each microtubule appears to make contact with its respective satellite, or is aligned so that it could contact one of the satellites, provided serial sections were cut and collected in order. After longer periods of recovery, the microtubules elongate; as before, one end of each makes contact with a satellite or is aligned so that it could attach to a satellite. Segments of microtubules seen in the basal region of the cell are aligned parallel to the long axis of the cell as in the untreated ectodermal cells and are therefore interpreted as extensions of those tubules making contact with one of the satellites. On the basis of these observations, we suggest that assembly of microtubules is initiated at the satellites. These sites, perhaps best referred to as "nucleating sites," thereby could exert considerable control over the distribution of microtubules in cells. It is hoped that this preliminary report will be followed up by a more detailed study using serial sections.

Animals↗