The outer of the three germ layers of an embryo.
The complex processes of initiating CELL DIFFERENTIATION in the embryo. The precise regulation by cell interactions leads to diversity of cell types and specific pattern of organization (EMBRYOGENESIS).
The developmental stage that follows BLASTULA or BLASTOCYST. It is characterized by the morphogenetic cell movements including invagination, ingression, and involution. Gastrulation begins with the formation of the PRIMITIVE STREAK, and ends with the formation of three GERM LAYERS, the body plan of the mature organism.
The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.
The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.
The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.
The entire nerve apparatus, composed of a central part, the brain and spinal cord, and a peripheral part, the cranial and spinal nerves, autonomic ganglia, and plexuses. (Stedman, 26th ed)
The inner of the three germ layers of an embryo.
Proteins obtained from various species of Xenopus. Included here are proteins from the African clawed frog (XENOPUS LAEVIS). Many of these proteins have been the subject of scientific investigations in the area of MORPHOGENESIS and development.
The development of anatomical structures to create the form of a single- or multi-cell organism. Morphogenesis provides form changes of a part, parts, or the whole organism.
A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.
The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.
Bone-growth regulatory factors that are members of the transforming growth factor-beta superfamily of proteins. They are synthesized as large precursor molecules which are cleaved by proteolytic enzymes. The active form can consist of a dimer of two identical proteins or a heterodimer of two related bone morphogenetic proteins.
Somewhat flattened, globular echinoderms, having thin, brittle shells of calcareous plates. They are useful models for studying FERTILIZATION and EMBRYO DEVELOPMENT.
The two longitudinal ridges along the PRIMITIVE STREAK appearing near the end of GASTRULATION during development of nervous system (NEURULATION). The ridges are formed by folding of NEURAL PLATE. Between the ridges is a neural groove which deepens as the fold become elevated. When the folds meet at midline, the groove becomes a closed tube, the NEURAL TUBE.
A bone morphogenetic protein that is a potent inducer of bone formation. It also functions as a regulator of MESODERM formation during EMBRYONIC DEVELOPMENT.
Proteins encoded by homeobox genes (GENES, HOMEOBOX) that exhibit structural similarity to certain prokaryotic and eukaryotic DNA-binding proteins. Homeodomain proteins are involved in the control of gene expression during morphogenesis and development (GENE EXPRESSION REGULATION, DEVELOPMENTAL).
The three primary germinal layers (ECTODERM; ENDODERM; and MESODERM) developed during GASTRULATION that provide tissues and body plan of a mature organism. They derive from two early layers, hypoblast and epiblast.
An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.
The region in the dorsal ECTODERM of a chordate embryo that gives rise to the future CENTRAL NERVOUS SYSTEM. Tissue in the neural plate is called the neuroectoderm, often used as a synonym of neural plate.
An early non-mammalian embryo that follows the MORULA stage. A blastula resembles a hollow ball with the layer of cells surrounding a fluid-filled cavity (blastocele). The layer of cells is called BLASTODERM.
The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.
The anatomical parts that make up an organism in the early stages of development.
The farthest or outermost projections of the body, such as the HAND and FOOT.
A fibroblast growth factor that preferentially activates FIBROBLAST GROWTH FACTOR RECEPTOR 4. It was initially identified as an androgen-induced growth factor and plays a role in regulating growth of human BREAST NEOPLASMS and PROSTATIC NEOPLASMS.
A family of small polypeptide growth factors that share several common features including a strong affinity for HEPARIN, and a central barrel-shaped core region of 140 amino acids that is highly homologous between family members. Although originally studied as proteins that stimulate the growth of fibroblasts this distinction is no longer a requirement for membership in the fibroblast growth factor family.
A process of complicated morphogenetic cell movements that reorganizes a bilayer embryo into one with three GERM LAYERS and specific orientation (dorsal/ventral; anterior/posterior). Gastrulation describes the germ layer development of a non-mammalian BLASTULA or that of a mammalian BLASTOCYST.
Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.
Distinct regions of mesenchymal outgrowth at both flanks of an embryo during the SOMITE period. Limb buds, covered by ECTODERM, give rise to forelimb, hindlimb, and eventual functional limb structures. Limb bud cultures are used to study CELL DIFFERENTIATION; ORGANOGENESIS; and MORPHOGENESIS.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
Transference of tissue within an individual, between individuals of the same species, or between individuals of different species.
Common name for two distinct groups of BIRDS in the order GALLIFORMES: the New World or American quails of the family Odontophoridae and the Old World quails in the genus COTURNIX, family Phasianidae.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
A cartilaginous rod of mesodermal cells at the dorsal midline of all CHORDATE embryos. In lower vertebrates, notochord is the backbone of support. In the higher vertebrates, notochord is a transient structure, and segments of the vertebral column will develop around it. Notochord is also a source of midline signals that pattern surrounding tissues including the NEURAL TUBE development.
Wnt proteins are a large family of secreted glycoproteins that play essential roles in EMBRYONIC AND FETAL DEVELOPMENT, and tissue maintenance. They bind to FRIZZLED RECEPTORS and act as PARACRINE PROTEIN FACTORS to initiate a variety of SIGNAL TRANSDUCTION PATHWAYS. The canonical Wnt signaling pathway stabilizes the transcriptional coactivator BETA CATENIN.
A transparent, biconvex structure of the EYE, enclosed in a capsule and situated behind the IRIS and in front of the vitreous humor (VITREOUS BODY). It is slightly overlapped at its margin by the ciliary processes. Adaptation by the CILIARY BODY is crucial for OCULAR ACCOMMODATION.
A family of transcription factors that control EMBRYONIC DEVELOPMENT within a variety of cell lineages. They are characterized by a highly conserved paired DNA-binding domain that was first identified in DROSOPHILA segmentation genes.
A family of VERTEBRATE homeodomain proteins that share homology with orthodenticle protein, Drosophila. They regulate GENETIC TRANSCRIPTION and play an important role in EMBRYONIC DEVELOPMENT of the BRAIN.
Genes that encode highly conserved TRANSCRIPTION FACTORS that control positional identity of cells (BODY PATTERNING) and MORPHOGENESIS throughout development. Their sequences contain a 180 nucleotide sequence designated the homeobox, so called because mutations of these genes often results in homeotic transformations, in which one body structure replaces another. The proteins encoded by homeobox genes are called HOMEODOMAIN PROTEINS.
Proteins obtained from the ZEBRAFISH. Many of the proteins in this species have been the subject of studies involving basic embryological development (EMBRYOLOGY).
The founding member of the nodal signaling ligand family of proteins. Nodal protein was originally discovered in the region of the mouse embryo primitive streak referred to as HENSEN'S NODE. It is expressed asymmetrically on the left side in chordates and plays a critical role in the genesis of left-right asymmetry during vertebrate development.
A region, of SOMITE development period, that contains a number of paired arches, each with a mesodermal core lined by ectoderm and endoderm on the two sides. In lower aquatic vertebrates, branchial arches develop into GILLS. In higher vertebrates, the arches forms outpouchings and develop into structures of the head and neck. Separating the arches are the branchial clefts or grooves.
Morphological and physiological development of EMBRYOS or FETUSES.
An individual that contains cell populations derived from different zygotes.
A family of intercellular signaling proteins that play and important role in regulating the development of many TISSUES and organs. Their name derives from the observation of a hedgehog-like appearance in DROSOPHILA embryos with genetic mutations that block their action.
Morphological and physiological development of EMBRYOS.
The upper part of the human body, or the front or upper part of the body of an animal, typically separated from the rest of the body by a neck, and containing the brain, mouth, and sense organs.
The developmental history of specific differentiated cell types as traced back to the original STEM CELLS in the embryo.
The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.
The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.
A genus of aquatic newts in the Salamandridae family. During breeding season many Triturus males have a dorsal crest which also serves as an accessory respiratory organ. One of the common Triturus species is Triturus cristatus (crested newt).
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A species of SEA URCHINS in the family Strongylocentrotidae found on the Pacific coastline from Alaska to Mexico. This species serves as a major research model for molecular developmental biology and other fields.
A subclass of SOX transcription factors that are expressed in neuronal tissue where they may play a role in the regulation of CELL DIFFERENTIATION. Members of this subclass are generally considered to be transcriptional activators.
Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.
The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).
Cells in certain regions of an embryo that self-regulate embryonic development. These organizers have been found in dorsal and ventral poles of GASTRULA embryos, including Spemann organizer in amphibians, and Hensen node in chicken and mouse. These organizer cells communicate with each other via a network of secreted signaling proteins, such as BONE MORPHOGENETIC PROTEINS and their antagonists (chordin and noggin).
Paired, segmented masses of MESENCHYME located on either side of the developing spinal cord (neural tube). Somites derive from PARAXIAL MESODERM and continue to increase in number during ORGANOGENESIS. Somites give rise to SKELETON (sclerotome); MUSCLES (myotome); and DERMIS (dermatome).
Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.
A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.
A HEPARIN binding fibroblast growth factor that may play a role in LIMB BUDS development.
A family of sequence-related proteins similar to HMGB1 PROTEIN that contains specific HMG-BOX DOMAINS.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
An exotic species of the family CYPRINIDAE, originally from Asia, that has been introduced in North America. They are used in embryological studies and to study the effects of certain chemicals on development.
A portion of the animal phylum Chordata comprised of the subphyla CEPHALOCHORDATA; UROCHORDATA, and HYPEROTRETI, but not including the Vertebrata (VERTEBRATES). It includes nonvertebrate animals having a NOTOCHORD during some developmental stage.
Activins are produced in the pituitary, gonads, and other tissues. By acting locally, they stimulate pituitary FSH secretion and have diverse effects on cell differentiation and embryonic development. Activins are glycoproteins that are hetero- or homodimers of INHIBIN-BETA SUBUNITS.
A post-MORULA preimplantation mammalian embryo that develops from a 32-cell stage into a fluid-filled hollow ball of over a hundred cells. A blastocyst has two distinctive tissues. The outer layer of trophoblasts gives rise to extra-embryonic tissues. The inner cell mass gives rise to the embryonic disc and eventual embryo proper.
A homeodomain protein that interacts with TATA-BOX BINDING PROTEIN. It represses GENETIC TRANSCRIPTION of target GENES and plays a critical role in ODONTOGENESIS.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A layer of cells lining the fluid-filled cavity (blastocele) of a BLASTULA, usually developed from a fertilized insect, reptilian, or avian egg.
Proteins that are preferentially expressed or upregulated during FETAL DEVELOPMENT.
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.
The posterior of the three primitive cerebral vesicles of an embryonic brain. It consists of myelencephalon, metencephalon, and isthmus rhombencephali from which develop the major BRAIN STEM components, such as MEDULLA OBLONGATA from the myelencephalon, CEREBELLUM and PONS from the metencephalon, with the expanded cavity forming the FOURTH VENTRICLE.
A tube of ectodermal tissue in an embryo that will give rise to the CENTRAL NERVOUS SYSTEM, including the SPINAL CORD and the BRAIN. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. For malformation of the neural tube, see NEURAL TUBE DEFECTS.
Congenital structural deformities of the upper and lower extremities collectively or unspecified.
A proto-oncogene protein and member of the Wnt family of proteins. It is expressed in the caudal MIDBRAIN and is essential for proper development of the entire mid-/hindbrain region.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Methods of maintaining or growing biological materials in controlled laboratory conditions. These include the cultures of CELLS; TISSUES; organs; or embryo in vitro. Both animal and plant tissues may be cultured by a variety of methods. Cultures may derive from normal or abnormal tissues, and consist of a single cell type or mixed cell types.
Proteins containing a region of conserved sequence, about 200 amino acids long, which encodes a particular sequence specific DNA binding domain (the T-box domain). These proteins are transcription factors that control developmental pathways. The prototype of this family is the mouse Brachyury (or T) gene product.
The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Members of the transforming growth factor superfamily that play a role in pattern formation and differentiation during the pregastrulation and GASTRULATION stages of chordate development. Several nodal signaling ligands are specifically involved in the genesis of left-right asymmetry during development. The protein group is named after a critical region of the vertebrate embryo PRIMITIVE STREAK referred to as HENSEN'S NODE.
A genus of aquatic newts belonging to the family Salamandridae and sometimes referred to as "spiny" tritons. There are two species P. waltlii and P. poireti. P. waltlii is commonly used in the laboratory. Since this genus adapts to aquarium living, it is easy to maintain in laboratories.
A genus of BIRDS in the family Phasianidae, order GALLIFORMES, containing the common European and other Old World QUAIL.
A Wnt protein subtype that plays a role in cell-cell signaling during EMBRYONIC DEVELOPMENT and the morphogenesis of the developing NEURAL TUBE. Defects in Wnt3 protein are associated with autosomal recessive tetra-AMELIA in humans.
A genus of SEA URCHINS in the family Strongylocentrotidae with a hemicyclic apical disk and short spines.
Goosecoid protein is a homeodomain protein that was first identified in XENOPUS. It is found in the SPEMANN ORGANIZER of VERTEBRATES and plays an important role in neuronal CELL DIFFERENTIATION and ORGANOGENESIS.
A potent osteoinductive protein that plays a critical role in the differentiation of osteoprogenitor cells into OSTEOBLASTS.
A subclass of LIM domain proteins that include an additional centrally-located homeodomain region that binds AT-rich sites on DNA. Many LIM-homeodomain proteins play a role as transcriptional regulators that direct cell fate.
Flat keratinous structures found on the skin surface of birds. Feathers are made partly of a hollow shaft fringed with barbs. They constitute the plumage.
A bone morphogenetic protein that is widely expressed during EMBRYONIC DEVELOPMENT. It is both a potent osteogenic factor and a specific regulator of nephrogenesis.
The anterior of the three primitive cerebral vesicles of the embryonic brain arising from the NEURAL TUBE. It subdivides to form DIENCEPHALON and TELENCEPHALON. (Stedmans Medical Dictionary, 27th ed)
The functional hereditary units of INSECTS.
VERTEBRATES belonging to the class amphibia such as frogs, toads, newts and salamanders that live in a semiaquatic environment.
Specific molecular sites or structures on cell membranes that react with FIBROBLAST GROWTH FACTORS (both the basic and acidic forms), their analogs, or their antagonists to elicit or to inhibit the specific response of the cell to these factors. These receptors frequently possess tyrosine kinase activity.
The SKELETON of the HEAD including the FACIAL BONES and the bones enclosing the BRAIN.
The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.

The surface ectoderm is essential for nephric duct formation in intermediate mesoderm. (1/1870)

The nephric duct is the first epithelial tubule to differentiate from intermediate mesoderm that is essential for all further urogenital development. In this study we identify the domain of intermediate mesoderm that gives rise to the nephric duct and demonstrate that the surface ectoderm is required for its differentiation. Removal of the surface ectoderm resulted in decreased levels of Sim-1 and Pax-2 mRNA expression in mesenchymal nephric duct progenitors, and caused inhibition of nephric duct formation and subsequent kidney development. The surface ectoderm expresses BMP-4 and we show that it is required for the maintenance of high-level BMP-4 expression in lateral plate mesoderm. Addition of a BMP-4-coated bead to embryos lacking the surface ectoderm restored normal levels of Sim-1 and Pax-2 mRNA expression in nephric duct progenitors, nephric duct formation and the initiation of nephrogenesis. Thus, BMP-4 signaling can substitute for the surface ectoderm in supporting nephric duct morphogenesis. Collectively, these data suggest that inductive interactions between the surface ectoderm, lateral mesoderm and intermediate mesoderm are essential for nephric duct formation and the initiation of urogenital development.  (+info)

Regulation of neurotrophin-3 expression by epithelial-mesenchymal interactions: the role of Wnt factors. (2/1870)

Neurotrophins regulate survival, axonal growth, and target innervation of sensory and other neurons. Neurotrophin-3 (NT-3) is expressed specifically in cells adjacent to extending axons of dorsal root ganglia neurons, and its absence results in loss of most of these neurons before their axons reach their targets. However, axons are not required for NT-3 expression in limbs; instead, local signals from ectoderm induce NT-3 expression in adjacent mesenchyme. Wnt factors expressed in limb ectoderm induce NT-3 in the underlying mesenchyme. Thus, epithelial-mesenchymal interactions mediated by Wnt factors control NT-3 expression and may regulate axonal growth and guidance.  (+info)

Fish swimbladder: an excellent mesodermal inductor in primary embryonic induction. (3/1870)

Swimbladder of the crucian carp, Carassius auratus, was found to be better as a vegatalizing tissue than other tissues, such as guinea-pig bone marrow, when presumptive ectoderm of Triturus gastrulae was used as reacting tissue. Swimbladder usually induced assemblies of highly organized mesodermal tissues, such as notochord, somites and pronephric tubules, some of which were covered by mesodermal epithelium without any epidermal covering. A special character of the effect of swimbladder was the rather frequent induction of solid balls of undifferentiated cells, which were identified as mesodermal or mesodermal and probably endodermal. These findings show that swimbladder has a strong and fast spreading vegetalizing effect on the responding presumptive ectoderm.  (+info)

Embryological study of a T/t locus mutation (tw73) affecting trophectoderm development. (4/1870)

Mouse embryos homozygous for the recessive lethal mutation tw73 show specific defects in trophectoderm shortly after implantation. The trophectoderm and ectoplacental cone fail to form the usual close association with the uterine decidua, and proliferation is markedly reduced. The embryo proper ceases to develop beyond the two-layered stage and degenerates and dies within 5 days of implantation.  (+info)

Bmp4 is required for the generation of primordial germ cells in the mouse embryo. (5/1870)

In many organisms the allocation of primordial germ cells (PGCs) is determined by the inheritance of maternal factors deposited in the egg. However, in mammals, inductive cell interactions are required around gastrulation to establish the germ line. Here, we show that Bmp4 homozygous null embryos contain no PGCs. They also lack an allantois, an extraembryonic mesodermal tissue derived, like the PGCs, from precursors in the proximal epiblast. Heterozygotes have fewer PGCs than normal, due to a reduction in the size of the founding population and not to an effect on its subsequent expansion. Analysis of beta-galactosidase activity in Bmp4(lacZneo) embryos reveals that prior to gastrulation, Bmp4 is expressed in the extraembryonic ectoderm. Later, Bmp4 is expressed in the extraembryonic mesoderm, but not in PGCs. Chimera analysis indicates that it is the Bmp4 expression in the extraembryonic ectoderm that regulates the formation of allantois and primordial germ cell precursors, and the size of the founding population of PGCs. The initiation of the germ line in the mouse therefore depends on a secreted signal from the previously segregated, extraembryonic, trophectoderm lineage.  (+info)

BMP7 acts in murine lens placode development. (6/1870)

Targeted inactivation of the Bmp7 gene in mouse leads to eye defects with late onset and variable penetrance (A. T. Dudley et al., 1995, Genes Dev. 9, 2795-2807; G. Luo et al., 1995, Genes Dev. 9, 2808-2820). Here we report that the expressivity of the Bmp7 mutant phenotype markedly increases in a C3H/He genetic background and that the phenotype implicates Bmp7 in the early stages of lens development. Immunolocalization experiments show that BMP7 protein is present in the head ectoderm at the time of lens placode induction. Using an in vitro culture system, we demonstrate that addition of BMP7 antagonists during the period of lens placode induction inhibits lens formation, indicating a role for BMP7 in lens placode development. Next, to integrate Bmp7 into a developmental pathway controlling formation of the lens placode, we examined the expression of several early lens placode-specific markers in Bmp7 mutant embryos. In these embryos, Pax6 head ectoderm expression is lost just prior to the time when the lens placode should appear, while in Pax6-deficient (Sey/Sey) embryos, Bmp7 expression is maintained. These results could suggest a simple linear pathway in placode induction in which Bmp7 functions upstream of Pax6 and regulates lens placode induction. At odds with this interpretation, however, is the finding that expression of secreted Frizzled Related Protein-2 (sFRP-2), a component of the Wnt signaling pathway which is expressed in prospective lens placode, is absent in Sey/Sey embryos but initially present in Bmp7 mutants. This suggests a different model in which Bmp7 function is required to maintain Pax6 expression after induction, during a preplacodal stage of lens development. We conclude that Bmp7 is a critical component of the genetic mechanism(s) controlling lens placode formation.  (+info)

Gap junction signalling mediated through connexin-43 is required for chick limb development. (7/1870)

During chick limb development the gap junction protein Connexin-43 (Cx43) is expressed in discrete spatially restricted domains in the apical ectodermal ridge (AER) and mesenchyme of the zone of polarising activity. Antisense oligonucleotides (ODNs) were used to investigate the role of Connexin-43 (Cx43) in the development of the chick limb bud. We have used unmodified ODNs in Pluronic F-127 gel, which is liquid at low temperature but sets at room temperature and so remains situated at the point of application. As a mild surfactant, the gel increases antisense ODN penetration and supplies ODNs to the embryo continually for 12-18 h. We have shown a strong decrease in Cx43 protein expression after application of specific antisense oligonucleotides but the abundance of a closely related protein, Connexin-32 (Cx32), was not affected. Application of antisense Cx43 ODNs at stages 8-15 HH before limb outgrowth resulted in dramatic limb phenotypes. About 40% of treated embryos exhibited defects such as truncation of the limb bud, fragmentation into two or more domains, or complete splitting of the limb bud into two or three branches. Molecular analysis of antisense treated embryos failed to detect Shh or Bmp-2 in anterior structures and suggested that extra lobes seen in nicked and split limbs were not a result of establishment of new signalling centres as found after the application of FGF to the flank. However, examination of markers for the AER showed a number of abnormalities. In severely truncated specimens we were unable to detect the expression of either Fgf-4 or Fgf-8. In both nicked and split limbs the expression of these genes was discontinuous. Down-regulation of Cx43 after the antisense application could be comparable to AER removal and results in distal truncation of the limb bud. Taken together these data suggest the existence of a feedback loop between the FGFs and signalling mediated by Cx43.  (+info)

Chick Barx2b, a marker for myogenic cells also expressed in branchial arches and neural structures. (8/1870)

We have isolated a new chicken gene, cBarx2b, which is related to mBarx2 in sequence, although the expression patterns of the two genes are quite different from one another. The cBarx2b gene is expressed in craniofacial structures, regions of the neural tube, and muscle groups in the limb, neck and cloaca. Perturbation of anterior muscle pattern by application of Sonic Hedgehog protein results in a posteriorization of cBarx2b expression.  (+info)

The regionalisation of cell fate in the embryonic ectoderm was studied by analyzing the distribution of graft-derived cells in the chimaeric embryo following grafting of wheat germ agglutinin-gold-labelled cells and culturing primitive-streak-stage mouse embryos. Embryonic ectoderm in the anterior region of the egg cylinder contributes to the neuroectoderm of the prosencephalon and mesencephalon. Cells in the distal lateral region give rise to the neuroectoderm of the rhombencephalon and the spinal cord. Embryonic ectoderm at the archenteron and adjacent to the middle region of the primitive streak contributes to the neuroepithelium of the spinal cord. The proximal-lateral ectoderm and the ectodermal cells adjacent to the posterior region of the primitive streak produce the surface ectoderm, the epidermal placodes and the cranial neural crest cells. Some labelled cells grafted to the anterior midline are found in the oral ectodermal lining, whereas cells from the archenteron are found in the ...
We wish to understand how limbs are positioned with respect to the dorso-ventral axis of the body in vertebrate embryos, and how different regions of limb bud ectoderm, i.e. dorsal ectoderm, apical ridge and ventral ectoderm, originate. Signals from dorsal and ventral ectoderm control dorso-ventral patterning while the apical ectodermal ridge (AER) controls bud outgrowth and patterning along the proximo-distal axis. We show, using cell-fate tracers, the existence of two distinct ectodermal compartments, dorsal versus ventral, in both presumptive limb and flank of early chick embryos. This organisation of limb ectoderm is the first direct evidence, in vertebrates, of compartments in non-neural ectoderm. Since the apical ridge appears to be confined to this compartment boundary, this positions the limb. The mesoderm, unlike the ectoderm, does not contain two separate dorsal and ventral cell lineages, suggesting that dorsal and ventral ectoderm compartments may be important to ensure appropriate ...
Cranial placodes are evolutionary innovations of vertebrates. However, they most likely evolved by redeployment, rewiring and diversification of preexisting cell types and patterning mechanisms. In the second part of this review we compare vertebrates with other animal groups to elucidate the evolutionary history of ectodermal patterning. We show that several transcription factors have ancient bilaterian roles in dorsoventral and anteroposterior regionalisation of the ectoderm. Evidence from amphioxus suggests that ancestral chordates then concentrated neurosecretory cells in the anteriormost non-neural ectoderm. This anterior proto-placodal domain subsequently gave rise to the oral siphon primordia in tunicates (with neurosecretory cells being lost) and anterior (adenohypophyseal, olfactory, and lens) placodes of vertebrates. Likewise, tunicate atrial siphon primordia and posterior (otic, lateral line, and epibranchial) placodes of vertebrates probably evolved from a posterior proto-placodal region in
Header}} ==Introduction== [[File:Trilaminar_embryo.jpg,thumb,300px,The trilaminar embryo]] The top layer of the early [[T#trilaminar embryo,trilaminar embryo]] germ layers ({{ectoderm}}, {{mesoderm}} and {{endoderm}}) formed by {{gastrulation}}. The ectoderm can be though of as having 4 early regions: neural plate, neural crest, surface ectoderm and placodes. Note that there are other pages describing neural (central nervous system; brain and spinal cord) and neural crest (peripheral nervous system; sensory and sympathetic ganglia). Epidermis (integumentary, skin contribution) development will be briefly mentioned due to its ectoderm origin. The ectoderm contributes to the human embryo: # nervous system, both central (neural plate) and peripheral ({{neural crest}}). # epidermis of the skin (surface ectoderm) and pigmented cells ({{neural crest}}). # head regions that contribution sensory and endocrine structures ({{placodes}}). # adrenal gland medullary cells ({{neural crest}}). {, ...
The ectoderm is established during mammalian gastrulation from the anterior-distal portion of the pre-streak primitive ectoderm. Although fated spatially, transplantation experiments demonstrate that at this early stage, the cells are pluripotent and retain the ability to contribute to tissues derived from other germ layers, such as mesoderm (Beddington, 1982; Lawson et al., 1991). As gastrulation proceeds, the ectodermal precursors move in a proximal and posterior direction (Lawson et al., 1991), so that at the completion of gastrulation they comprise the entire inner layer of the embryo. At this stage, the cells have lost pluripotence, and have a differentiation potential limited to the ectodermal lineages (Carey et al., 1995). In lower vertebrates, the formation of ectoderm proceeds via a bipotent intermediate, definitive ectoderm, which differentiates to form the two major ectodermal lineages: surface ectoderm and neurectoderm (Hemmati-Brivanlou and Melton, 1997). The transient and dynamic ...
A BMP regulatory network controls ectodermal cell fate decisions at the neural plate border.[2] During ectodermal patterning the neural crest and preplacodal ectoderm are specified in adjacent domains at the neural plate border. BMP signalling is required for specification of both tissues, but how it is spatially and temporally regulated to achieve this is not understood. Here, using a transgenic zebrafish BMP reporter line in conjunction with double-fluorescent in situ hybridisation, we show that, at the beginning of neurulation, the ventral-to-dorsal gradient of BMP activity evolves into two distinct domains at the neural plate border: one coinciding with the neural crest and the other abutting the epidermis. In between is a region devoid of BMP activity, which is specified as the preplacodal ectoderm. We identify the ligands required for these domains of BMP activity. We show that the BMP-interacting protein Crossveinless 2 is expressed in the BMP activity domains and is under the control of ...
Development of the human lens begins at the 4 mm embryonic stage. Unlike the rest of the eye, which is derived mostly from the neural ectoderm, the lens is derived from the surface ectoderm. The first stage of lens differentiation takes place when the optic vesicle, which is formed from outpocketings in the neural ectoderm, comes in proximity to the surface ectoderm. The optic vesicle induces nearby surface ectoderm to form the lens placode. At the 4 mm stage, the lens placode is a single monolayer of columnar cells. As development progresses, the lens placode begins to deepen and invaginate. As the placode continues to deepen, the opening to the surface ectoderm constricts and the lens cells forms a structure known as the lens vesicle. By the 10 mm stage, the lens vesicle has completely separated from the surface ectoderm. After the 10mm stage, signals from the developing neural retina induces the cells closest to the posterior end of the lens vesicle begin to elongate toward the anterior end ...
We have characterized the early stages of murine hindlimb morphogenesis in the legless (lgl)mutant and non-mutant littermates. Initially the entire ventral ectoderm expresses many genetic markers characteristic of the AER (en-1, fgf-8, msx-2, dlx-2, cd44, and cx-43). Subsequently, the expression dom …
In addition to nourishing the embryo, extra-embryonic tissues (EETs) contribute to early em-bryonic patterning, primitive hematopoiesis, and fetal health. These tissues are of major importance for human medicine, as well as for efforts to improve livestock efficiency, but they remain incompletely understood. In bovines, EETs are accessible easily, in large amounts, and prior to implantation. We took advantage of this system to describe, in vitro and in vivo, the cell types present in bovine EETs at Day 18 of development. Specifically, we characterized the gene expression patterns and phenotypes of bovine extra-embryonic ectoderm (or trophoblast; bTC), endoderm (bXEC), and mesoderm (bXMC) cells in culture and compared them to their respective in vivo micro-dissected cells. After a week of culture, certain characteristics (e.g., gene expression) of the in vitro cells were altered with respect to the in vivo cells, but we were able to identify cores of cell-type-specific (and substrate-independent) genes
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The role of β-amyloid (Aβ) in the pathogenesis of Alzheimers disease (AD) is still considered crucial. The state of Aβ aggregation is critical in promoting neuronal loss and neuronal function impairment. Recently, we demonstrated that Acetylcholine (ACh) is neuroprotective against the toxic effects of Aβ in the cholinergic LAN-2 cells. In biophysical experiments, ACh promotes the soluble Aβ peptide conformation rather than the aggregation-prone β-sheet conformation. In order to better understand the biological role of ACh in AD, we studied the effect of Aβ on the phosphorylation of the cytosolic phospholipase A2 (cPLA2) in the TB neuroectodermal cell line, which differentiates toward a neuronal phenotype when cultured in the presence of retinoic acid (RA). We chose the phosphorylated form of cPLA2 (Ser505, Phospho-cPLA2) as a biomarker to test the influence of ACh on the effects of Aβ in both undifferentiated and RA-differentiated TB cells. Our results show that TB cells are responsive ...
MITSUNAGA NAKATSUBO Keiko , KUSUNOKI Shinichiro , KAWAKAMI Hayato , AKASAKA Koji , AKIMOTO Yoshihiro Medical molecular morphology : official journal of the Japanese Society for Clinical Molecular Morphology 42(2), 63-69, 2009-06-01 医中誌Web 参考文献48件 ...
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Developmental expression of two closely related fibroblast growth factor receptors, bek and flg, is described from early postimplantation until advanced organogenesis. Transcripts of bek and flg were first seen in the primitive ectoderm of egg-cylinder- stage embryos. Later, starting with somitogenesis, and then throughout embryogenesis, they were actively transcribed both in the mesoderm and neuroectoderm. Bek was expressed also in the surface ectoderm and in various epithelia, whereas flg expression was restricted mainly to the mesenchyme. In the limb bud bek transcripts displayed a gradient-like distribution and appeared earlier than flg. The two receptors, in contrast to their almost identical ligand binding specificity, displayed distinct spatial specificities throughout development, suggesting that developmental localization may contribute to functional specificity. The role of bek and flg in gastrulation and in epithelial-mesenchymal interactions of organogenesis will be discussed. ...
Egfr signaling is required in a narrow medial domain of the head ectoderm (here called head midline ) that includes the anlagen of the medial brain (including the dorsomedial and ventral medial domain of the brain, termed DMD and VMD respectively), the visual system (optic lobe, larval eye) and the stomatogastric nervous system (SNS). These head midline cells differ profoundly from their lateral neighbors in the way they develop. Three differences are noteworthy: (1) Like their counterparts in the mesectoderm, the head midline cells do not give rise to typical neuroblasts by delamination, but stay integrated in the surface ectoderm for an extended period of time. (2) The proneural gene l sc, which transiently (for approximately 30 minutes) comes on in all parts of the procephalic neurectoderm while neuroblasts delaminate, is expressed continuously in the head midline cells for several hours. (3) Head midline cells, similar to ventral midline cells of the trunk, require the Egfr pathway. In ...
Images provided by Claire Anderson. The publication of Liem et al. 1995 (Liem Jr., K.F, Tremml G, Roelink H, Jessell T.M. Dorsal differentiation of neural plate cells induced by BMP-mediated signals from epidermal ectoderm. Cell. 1995; 82: 969-979. PMID: 7553857 ) was referred for the probe information. Authors indicated further probe information could be found in another publication (Francis PH, Richardson MK, Brickell PM, Tickle C. Bone morphogenetic proteins and a signalling pathway that controls patterning in the developing chick limb. Development. 1994 Jan;120(1):209-18. PMID: 8119128). The indicated probe sequence was extracted from NCBI (GenBank: X75914.1 ...
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Those plucky upstarts in the Rolling Stones have announced a new round of touring and a reissue of their beloved 1971 LP Sticky Fingers. Here are a few facts you should know going into the mania for Mick & Co. on Tuesday morning. 1. There's no L.A. date yet. The last time the Stones dipped through...
This forum is dedicated to an open discussion of all things Rolling Stones. From new fans to hardcore veterans, everyone is welcome. Forum is moderated lightly. The golden rule is in effect. Let the discussions run rampant, as long as personal insults stay at the door! ...
Ras - dorsal-ventral anterior localization (Ras-dva) family. Ras-dva subfamily. Ras-dva (Ras - dorsal-ventral anterior localization) subfamily consists of a set of proteins characterized only in Xenopus leavis, to date. In Xenopus Ras-dva expression is activated by the transcription factor Otx2 and begins during gastrulation throughout the anterior ectoderm. Ras-dva expression is inhibited in the anterior neural plate by factor Xanf1. Downregulation of Ras-dva results in head development abnormalities through the inhibition of several regulators of the anterior neural plate and folds patterning, including Otx2, BF-1, Xag2, Pax6, Slug, and Sox9. Downregulation of Ras-dva also interferes with the FGF-8a signaling within the anterior ectoderm. Most Ras proteins contain a lipid modification site at the C-terminus, with a typical sequence motif CaaX, where a = an aliphatic amino acid and X = any amino acid. Lipid binding is essential for membrane attachment, a key feature of most Ras proteins. ...
Bone morphogenetic protein 4, or BMP4, is a transforming growth factor that causes the cells of the ectoderm to differentiate into skin cells. Without BMP4 the ectoderm cells would develop into neural cells. Axial mesoderm cells under the ectoderm secrete inhibitory signals called chordin, noggin and follistatin. These inhibitory signals prevent the action of BMP4, which would normally make the cells ectoderm; as a result, the overlying cells take their normal course and develop into neural cells. The cells in the ectoderm that circumscribe these neural cells do not receive the BMP4 inhibitor signals and as a result BMP4 induces these cells to develop into skin cells.[8] Neural plate border specifiers are induced as a set of transcription factors. Distalless-5, PAX3 and PAX7 prevent the border region from becoming either neural plate or epidermis.[1] These induce a second set of transcription factors called neural crest specifiers, which cause cells to become neural crest cells. In a newly ...
BACKGROUND: The Brachyury (T) gene is required for the formation of posterior mesoderm and for axial development in both mouse and zebrafish embryos. In these species, and in Xenopus, the gene is expressed transiently throughout the presumptive mesoderm, and transcripts then persiste in notochord and posterior tissues. In Xenopus embryos, expression of the Xenopus homologue of Brachyury, Xbra, can be induced in presumptive ectoderm by basic fibroblast growth factor (FGF) and activin; in the absence of functional FGF or activin signalling pathways, expression of the gene is severely reduced. Ectopic expression of Xbra in presumptive ectoderm causes mesoderm to be formed. As Brachyury and its homologues encode sequence-specific DNA-binding proteins, it is likely that each functions by directly activating downstream mesoderm-specific genes. RESULTS: We show that expression in Xenopus embryos of RNA encoding a dominant-negative FGF receptor inhibits the mesoderm-inducing activity of Xbra. We ...
Eye formation in the human embryo begins at approximately three weeks into embryonic development and continues through the tenth week. Cells from both the mesodermal and the ectodermal tissues contribute to the formation of the eye. Specifically, the eye is derived from the neuroepithelium, surface ectoderm, and the extracellular mesenchyme which consists of both the neural crest and mesoderm. Neuroepithelium forms the retina, ciliary body, iris, and optic nerves. Surface ectoderm forms the lens, corneal epithelium and eyelid. The extracellular mesenchyme forms the sclera, the corneal endothelium and stroma, blood vessels, muscles, and vitreous. The eye begins to develop as a pair of optic vesicles on each side of the forebrain at the end of the 4th week of pregnancy. Optic vesicles are outgrowings of the brain which make contact with the surface ectoderm and this contact induces changes necessary for further development of the eye. Through a groove at the bottom of the optic vesicle known as ...
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The development of a vertebrate embryo is a complex process marked by several morphogenetic events, which create a highly reproducible pattern. The vertebrate limb has emerged as a model for studying pattern formation in the embryo mainly because limb manipulations do not affect embryo survival. Within the developing limb, experimental manipulation of the embryo resulted in the identification of the classical signaling centers known as the Zone of Polarizing Activity (ZPA) and the Apical Ectodermal Ridge (AER). The molecular signals required for function of the ZPA and AER have been identified. They are Sonic hedgehog (Shh) from the ZPA and Fibroblast Growth Factors (Fgfs) from the AER. The functions of each of these molecules are now beginning to be understood. Analysis of Shh and hedgehog (Hh) signaling target genes has shown that Hh activation in the limb bud mesoderm is required for normal limb development. It has been stated that Hh signaling in the limb bud ectoderm cannot occur because ...
Vertebrate sensory organs arise from epithelial thickenings called placodes. Along with neural crest cells, cranial placodes are considered ectodermal novelties that drove evolution of the vertebrate head. The anterior-most placode generates the endocrine lobe [adenohypophysis (ADH)] of the pituitary, a master gland controlling growth, metabolism, and reproduction. In addition to known ectodermal contributions, we use lineage tracing and time-lapse imaging in zebrafish to identify an endodermal contribution to the ADH. Single-cell RNA sequencing of the adult pituitary reveals similar competency of endodermal and ectodermal epithelia to generate all endocrine cell types. Further, endoderm can generate a rudimentary ADH-like structure in the near absence of ectodermal contributions. The fish condition supports the vertebrate pituitary arising through interactions of an ancestral endoderm-derived proto-pituitary with newly evolved placodal ectoderm. ...
A process that stimulates and directs a morphogenetic influence on a population of cells. These populations are often differentiating cells or adjacent neighboring cells that are not fixed on a developmental path. Embryonic induction plays a regulatory role in the development and construction of embryos.
TY - CHAP. T1 - The breast. AU - Heys, Steven D.. PY - 2006/1/1. Y1 - 2006/1/1. N2 - BASIC BIOLOGY; Anatomy of the breast; Embryology; The breast is a modified sweat gland which originates from the ectodermal layer of the embryo between the fifth and sixth week of gestation. It arises from the milk lines, which are two ridges of ectodermal thickening, running from the axilla to the groin. Although most of the milk line eventually disappears, a prominent ridge remains in the pectoral area to form the breast. The ectoderm in this area subsequently grows into the underlying mesoderm as a series (15-20) of buds. These ectodermal buds, which are initially solid, eventually form the lactiferous ducts and their associated alveoli. The adjacent mesenchyme develops into the surrounding adipose and connective tissues. During the final 2 months of gestation, the ducts become canalised and a mammary pit is formed in the ectoderm. The lactiferous ducts subsequently communicate with the mammary pit. ...
Ectoderm, Endoderm, and Mesoderm: What do the 3 Germ Cell Layers Give Rise To? Definitions, Table, and Easy Mnemonics for the 3 Germ Cell Layers
Ectoderm, Endoderm, and Mesoderm: What do the 3 Germ Cell Layers Give Rise To? Definitions, Table, and Easy Mnemonics for the 3 Germ Cell Layers
Neural brain development as well stem cell proliferation with circuits plus crest and mind ectoderm drosophila cells in tumor formation progenitor |
EV:0100003. EFO:0000414. MESH:A16.254.425.273. MIAA:0000173. ZFA:0000016. CALOHA:TS-0216. MAT:0000155. EMAPA:16069. GAID:1304. BILA:0000036. EHDAA2:0000428. XAO:0000001. BTO:0000315. TAO:0000016. MAT:0000173. VHOG:0000153. NCIT:C12703. UMLS:C0013574. FBbt:00000111. FMA:69070. AAO:0000137. ...
Zebrafish msxB, msxC and msxE function together to refine the neural-nonneural border and regulate cranial placodes and neural crest development. part 2
Previously, the researchers were not able to address the genes possible role in mouse eye formation because inactivation of Six3 significantly disrupted development of the area of the brain where the eye normally forms. The St. Jude team overcame this problem by taking advantage of Cre/loxP-technology, which allowed them to choose the time and place in which to remove Six3 function from specific cells. This permitted the investigators to remove Six3 activity from the presumptive lens ectoderm (PLE)--the area of the developing head where the lens will ultimately form in response to a series of biochemical signals. Following this systematic approach, the St. Jude team demonstrated that Six3 plays its important role in the PLE. The investigators also showed that a key consequence of removing Six3 during early development is that the PLE fails to undergo its normal thickening, an initial critical step in lens formation.. Our discovery helps to better unravel the regulatory pathway that controls ...
The main points in the foregoing paper maybe summarised as follows :. (1) A yolk nucleus of the type described by Bambeke, as occurring in the egg of Pholcus, is present in the developing egg of Flustrella hispida.. (2) Segmentation and cell-lineage have been followed out in detail up to the 32-cell stage.. (3) The formation of the endoderm has been traced.. (4) The oral and aboral ectoderm are differentiated as early as the 16-cell stage, and remain quite distinct from that time onwards.. (5) The ciliated ring of the larva is formed by the coalescence of several originally distinct rows of cells, and not by the hypertrophy of a single row.. (6) A stomach, comparable to that of Alcyonidium, is present also in Flustrella.. ...
The neural plate is a key developmental structure that serves as the basis for the nervous system. Opposite the primitive streak in the embryo, ectodermal tissue thickens and flattens to become the neural plate. The ends of the neural plate, known as the neural folds, push the ends of the plate up ...
The brain and spinal cord develop from the ectoderm. Following formation of the neural ectoderm, the neural preplate is formed and splits to form the neural plate. Closure of the neural plate forms the neural tube in a process called neurulation (see description in Neural Tube overview). The central hollow space of the neural tube later forms the fluid-filled brain ventricles. Neuroepithelium is generated in the neural tube walls and gives rise to immature nerve precursors called neuroblasts, the majority of which migrate and grow leading axonal appendages, and then aggregate in specific, genetically determined locations that will become the brainstem and spinal cord.The neuroectoderm then subdivides into ventricular and subventricular zones, which produce separate waves of migrating neuroblasts.. Following expansion of the anterior part of the neural tube and of the neural crest region, the tube twists and indentations appear and form the primary brain vesicles - the prosencephalon ...
As our bodies form, cells within the embryo divide and separate. Certain cells come together to form the outer layer, or ectoderm, of the early embryo, and give rise to tissue such as the skin and nervous system (spine, peripheral nerves and brain). Other cells come together to form the mesoderm or middle layer of the embryo, and eventually give rise to tissue like muscle, heart or bone. Once cells have been assigned to the different regions - mesoderm or ectoderm - a mysterious mechanism draws boundaries between them that mark their permanent separation. Any defect in these boundaries leads to disorganized mixing of cell populations, severe embryo abnormalities and eventually lethality.. Until now, adherence was thought to be the principle force responsible for the separation of the ectoderm from the mesoderm in embryonic cells. The Differential Adhesion Hypothesis used to explain the process of embryonic tissue separation - which has been accepted until now - postulates that cells from each ...
Now so far the little hollow bead of cells is basically two layers of tissue thick, an outer layer, called the ectoderm, and an inner layer, called the endoderm, and these are called your germ layers. For those organisms that stop developing at this point with that classy mouth-anus combo, they only get two germ layers. Theyre called diploblastic and they were born that way, its totally okay. But for more complex organisms whose mouths are separate from our anuses (Yes!), we develop a third layer of tissue, making us triploblasts. Here, the ectoderm is going to end up being the animals skin and nerves and spinal cord and most of its brain while the endoderm ends up becoming the digestive tract: the esophagus and colon and liver and stuff. And in addition some of the cells being breaking off between the endoderm and the ectoderm and form another layer called the mesoderm. These cells will eventually end up as the muscles and the circulatory system and the reproductive system, and, in the case ...
In the early 20th century, a set of famous experiments by Hans Spemann and Hilde Mangold showed that the formation of nervous tissue is induced by the underlying mesoderm. For decades, though, the nature of the induction process defeated every attempt to figure it out, until finally it was resolved by genetic approaches in the 1990s. Induction of neural tissue requires inhibition of the gene for a so-called bone morphogenetic protein, or BMP. Specifically the protein BMP4 appears to be involved. Two proteins called Noggin and Chordin, both secreted by the mesoderm, are capable of inhibiting BMP4 and thereby inducing ectoderm to turn into neural tissue. It appears that a similar molecular mechanism is involved for widely disparate types of animals, including arthropods as well as vertebrates. In some animals, however, another type of molecule called Fibroblast Growth Factor or FGF may also play an important role in induction ...
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22 days: … --, Ectoderm --, Superficial ectoderm and neuroectoderm --, Neuro plate --, Neural groove and Neural fold folds (Neural crest begin to form) --, Neural tube ...
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Ectoderm is one of three germ layers--groups of cells that coalesce early during the embryonic life of all animals except maybe sponges, and from which organs and tissues form. As an embryo develops, a single fertilized cell progresses through multiple rounds of cell division. Eventually, the clump of cells goes through a stage called gastrulation, during which the embryo reorganizes itself into the three germ layers: endoderm, ectoderm, and mesoderm. After gastrulation, the embryo goes through a process called neurulation, which starts the development of nervous system.. Format: Articles Subject: Processes ...
Figure 3. Clk2 promotes neural induction and suppresses epidermis differentiation via inhibition of BMP signal. (a) Clk2 induced neural tissues in X. laevis ectodermal explants. clk2‐GR and clk2 SYA‐GR mRNAs (500 pg, 1,000 pg and 1,500 pg) were injected into the animal hemisphere of 4‐cell stage embryos. At the blastula stage, embryos were transferred to a medium containing DEX and the ectodermal explants were isolated. At the neurula stage, the explants were subjected to an RT‐PCR analysis to examine the expression of marker genes. Expression of early neural markers (sip1, sox2 and sox3), an anterior neural marker (otx2) and a posterior neural marker (hoxb9) was upregulated by Clk2 overexpression, whereas the differentiated neural marker (ncam) was only slightly increased. The expression of epidermal keratin was reduced in the presence of Clk2. Embryo and −RT indicate whole embryos examined in the presence or absence of reverse transcriptase, respectively. histone h4 was used as ...
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Arl13b is a gene known to regulate ciliogenesis. Functional alterations in this genes activity have been associated with Joubert syndrome. We found that in Arl13 null mouse embryos the orientation of the optic cup is inverted, such that the lens is abnormally surrounded by an inverted optic cup whose retina pigmented epithelium is oddly facing the surface ectoderm. Loss of Arl13b leads to the dis ...
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For example, the ectoderm will give rise to the skin epidermis and the nervous system, the mesoderm will give rise to the ... "Ectoderm , The Embryo Project Encyclopedia". Retrieved 2019-11-07. "Mesoderm , The Embryo Project Encyclopedia ... For example, in neurogenesis, a subpopulation of cells from the ectoderm segregate from other cells and further specialize to ... During gastrulation of triploblastic animals, the three germinal layers that form are called the ectoderm, mesoderm, and ...
... the ectoderm and the endoderm. The endoderm lines the gastrovascular cavity, which is a water-filled sac, this acts as a ...
Ectoderm from the region of the dorsal lip of the blastopore of a developing salamander embryo was transplanted into another ... This began when boiled ectoderm was found to still be able induce by Johannes Holtfreter. Items as diverse as low pH, cyclic ... The process begins when the notochord induces the formation of the central nervous system (CNS) by signaling the ectoderm germ ... In secondary neurulation, the neural ectoderm and some cells from the endoderm form the medullary cord. The medullary cord ...
Bone morphogenetic protein 4 (BMP4) is released by the extra-embryonic ectoderm (ExE) at embryonic day 5.5 to 5.75 directly ... In mice, PGCs originate from the proximal epiblast, close to the extra-embryonic ectoderm (ExE), of the post-implantation ... Ying Y, Zhao GQ (April 2001). "Cooperation of endoderm-derived BMP2 and extraembryonic ectoderm-derived BMP4 in primordial germ ... ectoderm and mesoderm. The specification of primordial germ cells in mammals is mainly attributed to the downstream functions ...
The other two layers are the ectoderm (outside layer) and endoderm (inside layer), with the mesoderm as the middle layer ... The parietal layer together with overlying ectoderm forms the lateral body wall folds. The visceral layer forms the walls of ... During the third week a process called gastrulation creates a mesodermal layer between the endoderm and the ectoderm. This ... The remaining cells form the ectoderm. After that, the epiblast and the hypoblast establish contact with the extraembryonic ...
"Entrez Gene: EED embryonic ectoderm development". Cohen AS, Tuysuz B, Shen Y, Bhalla SK, Jones SJ, Gibson WT (Mar 2015). "A ... embryonic ectoderm development (EED), and functions as a transcriptional repressor". J. Biol. Chem. 278 (33): 30677-85. doi: ... embryonic ectoderm development (EED), and functions as a transcriptional repressor". J. Biol. Chem. 278 (33): 30677-85. doi: ...
The ectoderm develops into the surface ectoderm, neural crest, and the neural tube. The surface ectoderm develops into: ... The top layer is now called the ectoderm. The endoderm is one of the germ layers formed during animal embryonic development. ... The ectoderm generates the outer layer of the embryo, and it forms from the embryo's epiblast. ... The term "mesoderm" was introduced into English by Huxley in 1871, and "ectoderm" and "endoderm" by Lankester in 1873. Among ...
The outer wall will become the ectoderm. Later forming the epidermis and neural crest. In tunicates, invagination is the first ... Once the endoderm cells were invaginated, the cells will keep moving beneath the ectoderm. Later, the blastopore will be formed ... and ectoderm. More localized invaginations also occur later in embryonic development, The inner membrane of a mitochondrion ...
Neural development happens in the dorsal ectoderm. In the genus Xenopus, over expression of Dullard undergoes apoptosis in ...
It has its origin from oral ectoderm. It is one of the four major tissues which make up the tooth, along with dentin, cementum ...
The ectospermalege is derived from the ectoderm. It consists of a groove in the right-handed posterior margin of the fifth ...
The hindgut is a short invagination of the ectoderm, linking the midgut to the anus. It can be dilated and shortened by muscles ... Unlike the fore- and hindgut, which are derived from ectoderm, it has no cuticular lining. The midgut is surrounded by muscle ... The foregut (stomodeum) develops from the ectoderm. It is called pharynx before passing through the central nervous system, and ... which leads into a cuticle-lined duct derived from the ectoderm into the open through an organ (penis in males or ovipositor in ...
Without BMP4 the ectoderm cells would develop into neural cells. Axial mesoderm cells under the ectoderm secrete inhibitory ... Approximately half of those cells will be induced to remain ectoderm, while the other half will form the neural plate.[2][3] ... The cells in the ectoderm that circumscribe these neural cells do not receive the BMP4 inhibitor signals and as a result BMP4 ... In primary neurulation, the layer of ectoderm divides into three sets of cells: the neural tube (future brain and spinal cord ...
He concluded that when EDTA is used to remove the ectoderm from limb buds, regions towards the end of the limb do not form. ... In his 1948 publication "The proximo-distal sequence of origin of the parts of the chick wing and the role of the ectoderm," ... In 1962, Saunders published an article titled "On the role of ectoderm in limb development" in which he made several promising ... Additionally, Saunders's study indicated that when ultrasound is used to remove the ectoderm of the limb buds, some of them may ...
In the head: Neural crest cells migrate Neural tube closes Overlying ectoderm closes In the trunk: Overlying ectoderm closes ... BMP is initially secreted from the overlying ectoderm. A secondary signaling center is then established in the roof plate, the ... Primary neurulation divides the ectoderm into three cell types: The internally located neural tube The externally located ...
The mesoderm is formed from endoderm in the form of hollow pouches which come to lie between ectoderm and endoderm, The ... The buccal cavity is usually lined with ectoderm. So it is doubtful if buccal diverticulum is an endodermal structure. The true ...
Cells that remain in the epiblast become ectoderm. This is the trilaminar disc and the epiblast cells have given rise to the ... In the first week of human embryogenesis two layers of cells have formed, an external epiblast layer (the primitive ectoderm), ...
Embryos have three layers: endoderm, mesoderm and ectoderm. Each turns into various body parts. The nervous system grows from ... the ectoderm (which also contributes dental enamel and the epidermis). Ectodermal cells were placed into gel droplets and ...
BMPs induce the ectoderm to become epidermal ectoderm. Inhibition of BMPs allows neuroectoderm to arise from ectoderm, a ...
AMS generally results in abnormal ectoderm-derived structures. The most prominent abnormality is the underdevelopment ( ...
It can be found in endoderm or ectoderm. Myoepithelial cells are true epithelial cells positive for keratins, not to be ...
The lens vesicle is developed from surface ectoderm. It will separate from surface ectoderm at approximately day 33. Lens ...
Sea urchin ectoderm network from the Davidson Lab. Mouse ventral neural tube specification from the McMahon Lab. Environment ...
Ectoderm[3]. System. Integumentary[3]. Nerve. Eccrine: cholinergic sympathetic nerves[4]. Apocrine: adrenergic nerves[5]. ...
Meanwhile, the overlying ectoderm secretes bone morphogenetic protein (BMP). This induces the roof plate to begin to secrete ...
The ectoderm then differentiates into neural and epidermal tissue. In reptilian embryos, beginning in the late-stage neurula ... while the nonvascularized ectoderm-mesoderm outer layer, termed the somatopleure, becomes the amnion and chorion. During ...
The ectoderm is the outermost layer of the embryo. This happens towards the end of the third week of gestation (time period ... The Central Nervous System (CNS) and memory in the fetus develop from the ectoderm following fertilization via a process called ...
Hanley says that when embryos merge at an early stage, what happens is that one of them becomes the ectoderm, one the endoderm ... The nervous system forms from a fold in ectoderm. Gonads form from endoderm. And, each organ typically forms from one cell ...
However, the lens is necessary to act as an inducer for the ectoderm to transform it into the cornea. Surface ectoderm produces ... The eye is essentially a derivative of the ectoderm from the somatic ectoderm and neural tube, with a succession of inductions ... The interaction between the growing vesicle and the ectoderm causes the ectoderm to thicken at that point. This thickened ... Surface ectoderm forms the lens, corneal epithelium and eyelid. The extracellular mesenchyme forms the sclera, the corneal ...
This ectoderm underlies where the cerebral hemisphere will eventually be. When a fetus has acalvaria, the embryonic ectoderm is ... After this occurs, mesenchymal tissue migrates under the ectoderm. ... is problematic migration of the membranous neurocranium with respect to the normal positioning of the immature ectoderm. When ... pathogenesis of acalvaria is faulty migration of the membranous neurocranium with normal placement of the embryonic ectoderm, ...
The word ectoderm comes from the Greek ektos meaning "outside", and derma meaning "skin". Generally speaking, the ectoderm ... In vertebrate embryos, the ectoderm can be divided into two parts: the dorsal surface ectoderm also known as the external ... Mammalian teeth develop from ectoderm derived from the mesenchyme: oral ectoderm and neural crest. The epithelial components of ... is completely engulfed by the prospective ectoderm, as these top cells undergo epiboly, where the ectoderm cells divide in a ...
The surface ectoderm (or external ectoderm) forms the following structures: Skin (only epidermis; dermis is derived from ... dentin and dental pulp are formed from ectomesenchyme which is derived from ectoderm (specifically neural crest cells and ...
Large search returns make our pages slow to load. Therefore, some functionality has been disabled until you refine your search to bring the number of returned assay results under TBD ...
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB), Gene Ontology (GO ...
The ectoderm then goes on to give rise to a number of both internal and external structures. The ectoderm forms during ... In amphibians, the ectoderm is restricted to the animal region of the blastula until gastrulation, at … …the exterior ectoderm ... The Ectoderm forms: … It differentiates into three subtypes ▣ The surface ectoderm ▣ The neural crest ▣ The neural tube The ... At what point are the cells differentiated as ectoderm cells? The ectoderm can be though of as having 4 early regions: neural ...
The Differentiation of Gastrula Ectoderm in Medium Conditioned by Axial Mesoderm Message Subject (Your Name) has sent you a ... The Differentiation of Gastrula Ectoderm in Medium Conditioned by Axial Mesoderm. M. C. Niu and V. C. Twitty ...
1984) A Family of mRNAs Expressed in the Dorsal Ectoderm of Sea Urchin Embryos. In: Malacinski G.M., Klein W.H. (eds) Molecular ... Translation Product Gastrula Stage Rabbit Reticulocyte Lysate Dorsal Ectoderm Pluteus Stage These keywords were added by ... A Family of mRNAs Expressed in the Dorsal Ectoderm of Sea Urchin Embryos. ... Accumulation in embryogenesis of five mRNAs enriched in the ectoderm of the sea urchin pluteus. Develop. Biol. 87:308-318. ...
Patterning the embryonic ectoderm gives rise to defined domains of progenitors for cell types as diverse as neurons, neural ... BMP4 signalling initiates and controls the size of the surface ectoderm domain, the decision between neural crest and placodal ... their new Development paper in which they apply advanced in vitro culturing techniques to investigate embryonic ectoderm ...
... Luisa Guerrini,1 Antonio ... N. Radoja, L. Guerrini, N. L. Iacono et al., "Homeobox gene Dlx3 is regulated by p63 during ectoderm development: relevance in ... a direct target of Bmp signaling and encodes a transcriptional repressor blocking neural specification in the ventral ectoderm ...
The Bilateria are triploblastic (with true endoderm, mesoderm, and ectoderm) (...).[well established][VHOG] ... SYN LOOM ...
Ectoderms explanation free. What is Ectoderms? Meaning of Ectoderms medical term. What does Ectoderms mean? ... Looking for online definition of Ectoderms in the Medical Dictionary? ... ectoderm. (redirected from Ectoderms). Also found in: Dictionary, Thesaurus, Encyclopedia. ectoderm. [ek´to-derm] the outermost ... ectoderm. (ek´tədurm), n the outermost of the three primary cell layers of an embryo. The ectoderm gives rise to the nervous ...
Dynamic expression of chicken Sox2 and Sox3 genes in ectoderm induced to form neural tissue.. Rex M1, Orme A, Uwanogho D, ... We show that cSox3 is expressed throughout the ectoderm that is competent to form nervous tissue before neural induction. The ... The appearance of cSox2 in neural ectoderm represents one of the earliest molecular responses to neural induction documented ... cSox3 expression is also lost from non-neuronal ectoderm shortly after the neural plate becomes morphologically apparent. cSox2 ...
The pre-placodal ectoderm (PPE) is a specialized ectodermal region which gives rise to the sensory organs and other systems. ... Fam46a regulates BMP-dependent pre-placodal ectoderm differentiation in Xenopus Message Subject (Your Name) has sent you a ... Fam46a regulates BMP-dependent pre-placodal ectoderm differentiation in Xenopus. Tomoko Watanabe, Takayoshi Yamamoto, Kohei ... Fam46a regulates BMP-dependent pre-placodal ectoderm differentiation in Xenopus. Tomoko Watanabe, Takayoshi Yamamoto, Kohei ...
Antibodies for proteins involved in ectoderm and mesoderm interaction pathways, according to their Panther/Gene Ontology ...
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Leukemia inhibitory factor is expressed by the preimplantation uterus and selectively blocks primitive ectoderm formation in ... Leukemia inhibitory factor is expressed by the preimplantation uterus and selectively blocks primitive ectoderm formation in ... Leukemia inhibitory factor is expressed by the preimplantation uterus and selectively blocks primitive ectoderm formation in ... Leukemia inhibitory factor is expressed by the preimplantation uterus and selectively blocks primitive ectoderm formation in ...
In contrast, expression of dermomyotomal markers can be caused by a contact-dependent signal from surface ectoderm and a ... Patterning of mammalian somites by surface ectoderm and notochord: evidence for sclerotome induction by a hedgehog homolog.. ...
ectoderm answers are found in the Tabers Medical Dictionary powered by Unbound Medicine. Available for iPhone, iPad, Android, ... ectoderm is a topic covered in the Tabers Medical Dictionary. To view the entire topic, please sign in or purchase a ... Accessed 22 September 2018. ... ER - ...
Conversion of Xenopus ectoderm into neurons by NeuroD, a basic helix-loop-helix protein ... Conversion of Xenopus ectoderm into neurons by NeuroD, a basic helix-loop-helix protein ... Conversion of Xenopus ectoderm into neurons by NeuroD, a basic helix-loop-helix protein ... Conversion of Xenopus ectoderm into neurons by NeuroD, a basic helix-loop-helix protein ...
Definition: The portion of the embryonic ectoderm, including the preplacodal ectoderm, that does not give rise to nervous ...
Ectoderm to Mesoderm Lineage Switching During Axolotl Tail Regeneration Message Subject. (Your Name) has forwarded a page to ...
Oral-aboral ectoderm differentiation of sea urchin embryos is disrupted in response to calcium ionophore * * Akasaka Koji ... A hyaline layer protein that becomes localized to the oral ectoderm and foregut of sea urchin embryos COFFMAN J. A. ... Autonomous and non-autonomous differentiation of ectoderm in different sea urchin species WIKRAMANAYAKE A. H. ...
Xenopus embryonic ectoderm has become an attractive model for studies of cell polarity. An assay is described, in which ... Xenopus embryonic ectoderm has become an attractive model for studies of cell polarity. An assay is described, in which ... Polarized Translocation of Fluorescent Proteins in Xenopus Ectoderm in Response to Wnt Signaling. doi: 10.3791/2700 Published: ... Itoh, K., Sokol, S. Y. Polarized Translocation of Fluorescent Proteins in Xenopus Ectoderm in Response to Wnt Signaling. J. Vis ...
Chemical Genetics Identifies c-Src as an Activator of Primitive Ectoderm Formation in Murine Embryonic Stem Cells ... Chemical Genetics Identifies c-Src as an Activator of Primitive Ectoderm Formation in Murine Embryonic Stem Cells ... Chemical Genetics Identifies c-Src as an Activator of Primitive Ectoderm Formation in Murine Embryonic Stem Cells ... Chemical Genetics Identifies c-Src as an Activator of Primitive Ectoderm Formation in Murine Embryonic Stem Cells ...
The head surface ectoderm-specific enhancer of mouse Pax6 directs reporter expression in the derivatives of the ectoderm in the ... We identified a Pax6 protein-responsive element termed LE9 (52 bp in length) within the head surface ectoderm-specific enhancer ... Pax6 autoregulation mediated by direct interaction of Pax6 protein with the head surface ectoderm-specific enhancer of the ...
Oral/aboral ectoderm differentiation of the sea urchin embryo depends on a planar or secretory signal from the vegetal ... A hyaline layer protein that becomes localized to the oral ectoderm and foregut of sea urchin embryos COFFMAN J. A. ... Subequatorial cytoplasm plays an important role in ectoderm patterning in the sea urchin embryo Kominami Tetsuya , Akagawa ... Autonomous and non-autonomous differentiation of ectoderm in different sea urchin species WIKRAMANAYAKE A. H. ...
Cell-type heterogeneity in the early zebrafish olfactory epithelium is generated from progenitors within preplacodal ectoderm. ... Lineage reconstruction reveals an anterior preplacodal ectoderm origin for Gnrh3 neurons: photoconversion.. (A,B) Confocal ... This, in combination with cell type-specific markers, allows them to trace cells back to the preplacodal ectoderm. To address ... Lineage reconstruction reveals an anterior preplacodal ectoderm origin for Gnrh3 neurons. Gnrh3+ neurons associate closely with ...
... but dorsal ectoderm is more neural competent than ventral ectoderm. It is a tenable, but as yet untested possibility that the ... The ectoderm of early Xenopus gastrula is competent to become induced to neural tissue, ... higher neural competence of dorsal gastrula ectoderm is dependent on the presence of t … ... The ectoderm of early Xenopus gastrula is competent to become induced to neural tissue, but dorsal ectoderm is more neural ...
... the primitive ectoderm, definitive ectoderm and neurectoderm. The existence of a definitive ectoderm progenitor in mammals has ... The ectoderm is established during mammalian gastrulation from the anterior-distal portion of the pre-streak primitive ectoderm ... Several approaches have been reported for the direction of ES cells to cells of the neural ectoderm or surface ectoderm ... In X. laevis, neurectoderm and surface ectoderm are established from a common bipotent progenitor, the definitive ectoderm, ...
  • He began his studies in embryology using chicken eggs, which allowed for his discovery of the ectoderm, mesoderm and endoderm. (
  • Like the other two germ layers - i.e., the mesoderm and endoderm - the ectoderm forms shortly after fertilization, after which rapid cell division begins. (
  • The position of the ectoderm relative to the other germ layers of the embryo is governed by "selective affinity", meaning that the inner surface of the ectoderm has a strong (positive) affinity for the mesoderm, and a weak (negative) affinity for the endoderm layer. (
  • These two processes allow for the prospective mesoderm cells to be placed between the ectoderm and the endoderm. (
  • Once convergent extension and radial intercalation are underway, the rest of the vegetal pole, which will become endoderm cells, is completely engulfed by the prospective ectoderm, as these top cells undergo epiboly, where the ectoderm cells divide in a way to form one layer. (
  • During week 3 of development the embryo undergoes gastrulation where the cells in the epiblast layer form a three-layered trilaminar disc with an ectoderm, mesoderm and endoderm layer. (
  • In fish and birds the future endoderm and mesoderm cells migrate inwards in a process called introgression, leaving the cells that remain on the outside surface as the future ectoderm cells. (
  • it is found between the ectoderm and endoderm. (
  • In amphibians, the ectoderm is restricted to the animal region of the blastula until gastrulation, at … …the exterior ectoderm, the middle mesoderm, and the interior endoderm. (
  • mesoderm endoderm notochord ectoderm. (
  • The outer layer of cells in the embryo, after establishment of the three primary germ layers (e.g., ectoderm, mesoderm, endoderm). (
  • Using molecular markers to follow the differentiation of defined cell types, we demonstrate that LIF selectively inhibits the formation of primitive ectoderm, while permitting the differentiation of primitive endoderm. (
  • The top layer of the early trilaminar embryo germ layers ( ectoderm , mesoderm and endoderm ) formed by gastrulation . (
  • Notch signaling in the division of germ layers in bilaterian embryos [3] "Bilaterian embryos are triploblastic organisms which develop three complete germ layers (ectoderm, mesoderm, and endoderm). (
  • While the ectoderm develops mainly from the animal hemisphere, there is diversity in the location from where the endoderm and the mesoderm arise in relation to the animal-vegetal axis, ranging from endoderm being specified between the ectoderm and mesoderm in echinoderms, and the mesoderm being specified between the ectoderm and the endoderm in vertebrates. (
  • Here, the single-layered and hollow blastula is rearranged and differentiated in the multi-layered gastrula with three distinct layers: the ectoderm, mesoderm, and endoderm. (
  • Based on the incorporation of 'derm' in all three of the terms - ectoderm, endoderm, and mesoderm - we can understand that ectoderm, endoderm, and mesoderm are all related to layers, specifically germ cell layers. (
  • We have three primary germ cell layers: the ectoderm, endoderm, and mesoderm. (
  • Here's a general summary: What Do the Ectoderm, Endoderm, and Mesoderm Develop Into? (
  • Practice Test Questions: Mesoderm, Endoderm, Ectoderm - Good luck! (
  • is formed between the ectoderm and endoderm during gastrulation, and the process is termed triploblastic development. (
  • What does the endoderm mesoderm and ectoderm become? (
  • The other two layers are the ectoderm (outside layer) and endoderm (inside layer), with the mesoderm as the middle layer between them. (
  • These three layers, the endoderm, the ectoderm and the mesoderm, are called the primary germ layers. (
  • During the stage of neural plate formation the embryo consists of three cell layers: the ectoderm that eventually forms the skin and neural tissues, the mesoderm that forms muscle and bone, and the endoderm that will form the cells lining the digestive and respiratory tracts. (
  • These pluripotent cells can differentiate into ectoderm, mesoderm, or endoderm. (
  • I propose that this direct activation of a set of regulatory genes enables a uniform regulatory response and a clear cut cell fate decision in the endoderm and in the dorsal ectoderm. (
  • The three germ layers in the chordate gastrula are called the endoderm , mesoderm , and ectoderm . (
  • In our following description of the structure and function of these germ layers, we will move from the innermost germ layer--the endoderm--and proceed outward to the outermost germ layer--the ectoderm. (
  • The mesoderm is made up of a variety of sub-types, each of which is signaled to differentiate into organs and tissues by cell-to-cell chemical interactions with the endoderm and ectoderm. (
  • The hallmark of vertebrate gastrulation is the reorganization of the inner cell mass (ICM) into the three germ layers: ectoderm, mesoderm, and endoderm. (
  • The ectoderm is one of the three primary germ layers formed in early embryonic development. (
  • Ectoderm, the outermost of the three germ layers, or masses of cells, which appears early in the development of an animal embryo. (
  • Ectoderm definition is - the outermost of the three primary germ layers of an embryo that is the source of various tissues and structures (such as the … A dorsal pathway through the dermis where they will enter the ectoderm through holes in the basal lamina to form melanocytes in the skin and hair follicles. (
  • The presence of an inhibitor-resistant c-Src mutant, but not analogous mutants of Hck, Lck, c-Yes, or Fyn, reversed the differentiation block associated with inhibitor treatment, resulting in the formation of cells with properties of primitive ectoderm. (
  • This previously unidentified progenitor occurs as a temporally discrete population during ES cell differentiation, and differs from the preceding and succeeding populations in gene expression and differentiation potential, with the unique ability to form surface ectoderm in response to BMP4 signalling. (
  • The transient and dynamic appearance of differentiation intermediates during mammalian gastrulation, and the complex differentiation environment created within the embryo, has precluded identification of definitive ectoderm in mammals. (
  • The ability to form, recognize and manipulate the differentiation of definitive ectoderm is crucial to understanding the determination of cell fate in the ectoderm. (
  • Sox3 regulates both neural fate and differentiation in the zebrafish ectoderm. (
  • In vertebrate embryos, the ectoderm can be divided into two parts: the dorsal surface ectoderm also known as the external ectoderm, and the neural plate, which invaginates to form the neural tube and neural crest. (
  • In contrast, expression of dermomyotomal markers can be caused by a contact-dependent signal from surface ectoderm and a diffusible signal from dorsal neural tube. (
  • The ectoderm of early Xenopus gastrula is competent to become induced to neural tissue, but dorsal ectoderm is more neural competent than ventral ectoderm. (
  • It is a tenable, but as yet untested possibility that the higher neural competence of dorsal gastrula ectoderm is dependent on the presence of the dorsal mesoderm. (
  • We found that this elevated the level of neural competence of ventral ectoderm to that of dorsal ectoderm. (
  • The effect of Xwnt-8 on neural competence of ventral ectoderm was strictly correlated with its ability to enhance the amount of dorsal structures. (
  • The data indicate that the presence of dorsal mesoderm is a prerequisite for establishing the differences in neural competence between gastrula dorsal and ventral ectoderm. (
  • Thus, in X. laevis embryos, the ectoderm is patterned by the secretion of BMP antagonists from the dorsal blastopore lip, or Spemann's organizer: BMP signalling is active ventrally, and induces the formation of surface ectoderm, whereas dorsal BMP signalling is inhibited, and the cells adopt a neural fate ( Hemmati-Brivanlou and Melton, 1997 ). (
  • These signals are initially expressed throughout the surface ectoderm, suggesting that another signal might be involved in patterning the optic vesicle initially into a dorsal RPE and ventral NR domain. (
  • During optic vesicle stages WNT-family members are expressed in the dorsal ectoderm and in the presumptive RPE. (
  • We propose a new model, where the optic vesicle is initially patterned into a dorsal RPE domain by both BMP and WNT signals released from the overlying ectoderm, while ventrally BMPs and FGFs are involved in NR specification. (
  • In order to define the transcriptome of small groups of cells from a single germ layer and to retain spatial information, dorsal and ventral ectoderm was subdivided along the anterior-posterior and medial-lateral axes by microdissections. (
  • This provides a genetic code to define positional information of any ectoderm sample along the anterior-posterior and dorsal-ventral axes directly from its transcriptome. (
  • En-1 blocks Wnt-7a expression, preventing expression of Lmx-1b there, and establishes the dorsal-ventral axis. (
  • The ectoderm can first be observed in amphibians and fish during the later stages of gastrulation. (
  • Early in development, when the embryo has undergone several cell divisions (cleavage) but has not yet begun gastrulation, cells in the upper animal region are already earmarked as future ectoderm cells.Gastrulation proceeds differently in different organisms. (
  • At the end of gastrulation, the anterior neural plate border of the zebrafish embryo gives rise to two specialized regions of ectoderm: the preplacodal ectoderm (PPE) that will ultimately produce the cranial placodes, and the cranial neural crest (CNC). (
  • The ectoderm is established during mammalian gastrulation from the anterior-distal portion of the pre-streak primitive ectoderm. (
  • The ectoderm originates in the epiblast , and is formed during gastrulation. (
  • This article will give a brief overview of the ectoderm, which is one of the three layers of the early tri-laminar embryo formed by gastrulation during early development. (
  • The origin of these defects is the abnormal patterning of the ectoderm during gastrulation. (
  • The outer layer of a blastula that gives rise to the ectoderm after gastrulation. (
  • The measurements showed that pHi decreases in explants of both neurectoderm and uninduced ectoderm during the time course of gastrulation, this pHi decrease thus fails to correlate with neural induction. (
  • In mammals, the primitive ectoderm is an epithelium of polarized cells that undergoes gastrulation and differentiates into all embryonic tissues. (
  • Xenopus embryonic ectoderm has become an attractive model for studies of cell polarity. (
  • In Xenopus laevis , BMP4 has been shown to suppress neural tissue and induce surface ectoderm from the definitive ectoderm ( Wilson and Hemmati-Brivanlou, 1995 ). (
  • The ability of noradrenaline to induce a neural fate was tested in naive ectoderm caps cut from late blastula stage Xenopus embryos. (
  • Expression of Xenopus snail in mesoderm and prospective neural fold ectoderm. (
  • Here, we trace the origins of the defects associated with the interference of XREST/NRSF function to the acquisition of the cell fates of the ectoderm, using an inducible dominant-negative (dn) XREST/NRSF form and a morpholino-modified antisense oligonucleotide in Xenopus embryos (MoREST). (
  • These results show that distinct SFK signaling pathways regulate mES cell fate and demonstrate that the formation of primitive ectoderm is regulated by the activity of c-Src. (
  • These cells, named early primitive ectoderm-like (EPL) cells, recapitulate in vivo development of the pre-implantation inner cell mass to the postimplantation primitive ectoderm. (
  • EPL cells maintain expression of the naïve marker Rex1 and upregulate expression of the primitive ectoderm genes Dnmt3b and Fgf5. (
  • The primitive ectoderm cell layer of EBs represents the primitive ectoderm of the early embryo. (
  • We find that in primitive ectoderm cells, ceramide was elevated and asymmetrically distributed to the apico-lateral cell membrane, where it was co-distributed with Cdc42 and F-actin. (
  • Pharmacological or siRNAmediated inhibition of ceramide biosynthesis impaired primitive ectoderm formation and concomitantly increased apoptosis in EBs. (
  • Primitive ectoderm formation was restored by incubation with ceramide or a ceramide analog, indicating that the observed defect was due to loss of ceramide. (
  • Taken together, our data suggest a novel mechanism by which a ceramide-induced, apico-lateral polarity complex with aPKC regulates primitive ectoderm cell polarity and morphogenesis. (
  • A family of proteins accumulating in ectoderm of sea urchin embryos specified by two related cDNA clones. (
  • In parallel, we use nonnegative matrix factorization to predict enhanced gene expression maps onto early and mid-neurula embryos, and specific signatures for each ectoderm area. (
  • Meis transcription factor maintains the neurogenic ectoderm and regulates the anterior-posterior patterning in embryos of a sea urchin, Hemicentrotus pulcherrimus [4] "Precise body axis formation is an essential step in the development of multicellular organisms, for most of which the molecular gradient and/or specifically biased localization of cell-fate determinants in eggs play important roles. (
  • Generally speaking, the ectoderm differentiates to form epithelial and neural tissues (spinal cord, peripheral nerves and brain). (
  • The surface ectoderm gives rise to most epithelial tissues, and the neural plate gives rise to most neural tissues. (
  • The ectoderm gives rise to the nervous system, the organs of special sense, the epidermis, and epidermal tissues such as fingernails, hair, and skin glands. (
  • We therefore measured pHi in explants of gastrula ectoderm and neurectoderm and identified ion exchangers that regulate pHi in these tissues. (
  • The ectoderm forms epithelial cells and tissues, and neuronal tissues. (
  • The pre-placodal ectoderm (PPE) is a specialized ectodermal region which gives rise to the sensory organs and other systems. (
  • Our results suggest that rather than originating from separate ectodermal populations, cell-type heterogeneity is generated from overlapping pools of progenitors within the preplacodal ectoderm. (
  • In lower vertebrates, the formation of ectoderm proceeds via a bipotent intermediate, definitive ectoderm, which differentiates to form the two major ectodermal lineages: surface ectoderm and neurectoderm ( Hemmati-Brivanlou and Melton, 1997 ). (
  • The ability to progress via a definitive ectoderm intermediate will underpin the development of rational and efficient methodologies for the derivation of specific ectodermal cell populations from pluripotent cells in culture for use as experimental models or to produce cells with therapeutic applications. (
  • The surface ectoderm will give rise to the epidermis, external glands, hair, nails, anterior pituitary, and the apical ectodermal ridge amongst others. (
  • The pathophysiology of ectodermal dysplasias involves a complex set of genes and gene products that result in alteration of pathways necessary for proper development of the ectoderm. (
  • An assay is described, in which subcellular distribution of fluorescent proteins is assessed in ectoderm cells. (
  • Bone morphogenetic proteins (BMPs) and FGFs are expressed in the surface ectoderm and are involved in RPE and NR specification respectively. (
  • One such gene us the EDA gene, which is a part of a group of genes that provide instructions for making proteins such as ectodysplasin A. Ectodysplasin A is part of a group of proteins that are important in signaling for the interactions between the ectoderm and the mesoderm. (
  • As ectoderm constitutes the outer most germ layer of gastrula, option b. is correct. (
  • The first major process here is neurulation, wherein the ectoderm differentiates to form the neural tube, neural crest cells and the epidermis. (
  • During neurulation, a region of central ectoderm becomes thickened to form the neural plate which then folds upon itself to generate the neural tube, from which all neurons and glia cells of the central nervous system arise. (
  • A molecular atlas of the developing ectoderm defines neural, neural crest, placode, and nonneural progenitor identity in vertebrates [1] "During vertebrate neurulation, the embryonic ectoderm is patterned into lineage progenitors for neural plate, neural crest, placodes and epidermis. (
  • In primary neurulation, the layer of ectoderm divides into three sets of cells: the neural tube (future brain and spinal cord), epidermis (skin) , and neural crest cells (connects epidermis and neural tube and will migrate to make neurons , glia , and skin cell pigmentation). (
  • The ectoderm cells differentiate into cells that form a number of external structures such as skin, sweat glands, skin sensor receptors, and hair follicles. (
  • from it is derived the epithelial lining of the primordial gut and the epithelial component of the glands and other structures (for example, lower respiratory system) that develop as … As the name suggests, the ectoderm is the germ layer that covers the outside of the embryo ('ecto' meaning outside). (
  • Alphabetical list of anatomical structures derived from ectoderm . (
  • These interactions are essential for the formation of several structures that arise from the ectoderm, including the skin, hair, nails, teeth and sweat glands. (
  • Surface ectoderm gives rise to all of the following structures except. (
  • Structures derived from neural ectoderm include Iris & Ciliary body Epithelium, Smooth muscles of iris (constrictor & dilator pupilae), Retina (REE & 9 sensory layers), Vitreous parts, Optic Nerve, Cup and Vesicle. (
  • For instance, while ciliated sensory neurons arise from preplacodal ectoderm (PPE), previous lineage tracing studies suggest that both Gonadotropin releasing hormone 3 (Gnrh3) and microvillous sensory neurons derive from cranial neural crest (CNC). (
  • Using a previously established mouse ES-cell-based system that recapitulates the development of the ectoderm lineage we have identified a transient population that is consistent with definitive ectoderm. (
  • The ectoderm is the outermost germ layer. (
  • Ectoderm is usually referred to as the outer layer. (
  • The ectoderm is the outer layer of an embryo that develops into the epidermis , derivatives of the epidermis , parts of the mouth and eye (like the cornea , lens , and retina ), and most of the nervous system. (
  • It differentiates into outer surface ectoderm and inner neuroectoderm, which gives rise to neural crest cells. (
  • The neurotransmitter noradrenaline drives noggin-expressing ectoderm cells to activate N-tubulin and become neurons. (
  • epidermis of the skin (surface ectoderm) and pigmented cells ( neural crest ). (
  • This suggests that after cells transition from naïve mESCs, they diverge and are fated to become either ectoderm (from EPL cells), or mesendoderm (from EpiSCs). (
  • Approximately half of those cells will be induced to remain ectoderm, while the other half will form the neural plate. (
  • During embryonic development, the entire nervous system, the skin and the sensory organs emerge from a single sheet of cells known as the ectoderm. (
  • For example, some cells in the ectoderm will express the genes specific to skin cells. (
  • During the formation of the neural system, special signaling molecules called growth factors signal some cells at the edge of the ectoderm to become epidermis cells. (
  • If the signaling by growth factors were disrupted, then the entire ectoderm would differentiate into neural tissue. (
  • Likewise, while the surface ectoderm becomes the epidermis, the neuroectoderm is induced along the neural pathway by the notochord, which is typically positioned above it. (
  • Pigment granules appear in the basal…, …tube detaches from the skin ectoderm and sinks beneath the surface. (
  • BMP4 signalling initiates and controls the size of the surface ectoderm domain, the decision between neural crest and placodal fates is determined by the relative levels of BMP and WNT signalling, and, finally, a combinatorial logic of WNT and BMP signalling drives neural crest specification. (
  • The surface ectoderm gives rise to the crystalline lens, the lacrimal gland, the meibomian glands, the corneal and conjunctival epithelium and the epidermis of the eyelids. (
  • Patterning of mammalian somites by surface ectoderm and notochord: evidence for sclerotome induction by a hedgehog homolog. (
  • The head surface ectoderm-specific enhancer of mouse Pax6 directs reporter expression in the derivatives of the ectoderm in the eye, such as lens and cornea, but the molecular mechanism of its control remains largely unknown. (
  • We identified a Pax6 protein-responsive element termed LE9 (52 bp in length) within the head surface ectoderm-specific enhancer. (
  • The current model of optic vesicle patterning assumes, that distally Fibroblast Growth Factors (FGFs) released from the overlying surface ectoderm are involved in NR specification, while proximally signals released from the ocular mesenchyme are involved in RPE specification. (
  • The ectoderm gives rise to two distinct lineages, namely, the surface ectoderm and the neural ectoderm . (
  • The ectoderm can be though of as having 4 early regions: neural plate, neural crest, surface ectoderm and placodes. (
  • The functions of the surface ectoderm include hormone regulation by the adenohypophysis, acting as a barrier against the external involvement, and homeostasis. (
  • Using conditional knockout mice, here we address the question that whether ocular surface ectoderm-derived Smad4 modulates retinal development. (
  • We found that loss of Smad4 specifically on surface lens ectoderm leads to microphthalmia and dysplasia of retina. (
  • Microarray analyses revealed that members of Hedgehog and Wnt signaling pathways are affected in the knockout retinas, suggesting that ocular surface ectoderm-derived Smad4 can regulate Hedgehog and Wnt signaling in the retina. (
  • Our studies suggest that defective of ocular surface ectoderm may affect retinal development. (
  • forms as the neural folds fuse in the midline and separate from the surface ectoderm. (
  • lies between the surface ectoderm and the notochord. (
  • The portion of the embryonic ectoderm, including the preplacodal ectoderm, that does not give rise to nervous tissue. (
  • The ectoderm that fails to involute will form the epidermis of the skin, hair, exocrine glands, and the anterior pituitary. (
  • The ectoderm develops into the skin, the nervous system, and the sense organs. (
  • We show that cSox3 is expressed throughout the ectoderm that is competent to form nervous tissue before neural induction. (
  • cSox2 expression increases dramatically in the central nervous system as neural ectoderm is established. (
  • The ectoderm forms the central and peripheral nervous system s and epidermis , and contributes to the adipose and heart as well as to numerous other organs. (
  • The neural plate, a thickened area of ectoderm, gives rise to the nervous system. (
  • From the ectoderm are formed the integuments, nervous system, sensory organs, anterior and posterior sections of the digestive tract, external gills, and ectomesenchyme. (
  • In general, ectoderm develops into parts of the skin, the brain and the nervous system. (
  • Generally speaking , the ectoderm differentiates to form the nervous system (spine, peripheral nerves and brain), tooth enamel and the epidermis (the outer part of integument). (
  • Dynamic expression of chicken Sox2 and Sox3 genes in ectoderm induced to form neural tissue. (
  • The neuro-ectoderm will form the neural tube and the neural crest. (
  • At approximately the third week of gestation, or development, the neural tube begins to form within the ectoderm layer. (
  • The ectoderm is a germ layer, or tissue layer, that forms in an animal embryo during development. (
  • First author George Britton and his supervisor Aryeh Warmflash discuss their new Development paper in which they apply advanced in vitro culturing techniques to investigate embryonic ectoderm patterning. (
  • MBS9341948 is a ready-to-use microwell, strip plate ELISA (enzyme-linked immunosorbent assay) Kit for analyzing the presence of the embryonic ectoderm development (EED) ELISA Kit target analytes in biological samples. (
  • Epidermis (integumentary, skin contribution) development will be briefly mentioned due to its ectoderm origin. (
  • EED (Embryonic Ectoderm Development) is a Protein Coding gene. (
  • Which of the following is a derivative of the ectoderm of the trilaminar embryo? (
  • The central region of the ectoderm forms the neural tube, which gives rise to the brain and the spinal cord. (
  • Our findings are consistent with the need of XREST/NRSF function for the appropriate patterning of the ectoderm, at least in part through mechanisms that involve the modification of bone morphogenetic protein (BMP) signaling. (
  • The ectoderm in the dorsum of the developing limb bud secretes a protein called wingless-type mouse mammary tumor virus integration site 7a (Wnt-7a). (
  • The neuroectoderm (neural ectoderm) will form the retina, retinal pigment epithelium, the pigmented and non-pigmented layers of the ciliary and iris epithelium, the dilator and sphincter muscles of the iris and the optic nerve fibres. (
  • Right now there is no effective treatment for the disease, and the underlying mechanisms, especially how retinal dysplasia develops from microphthalmia and whether it depends on the signals from lens ectoderm are still unclear. (