über Induktion von Embryonalanlagen durch Implantation artfremder Organisatoren

Spemann, Hans; Mangold, Hilde

doi:10.1007/bf02108133

Cited by 496 publications

(174 citation statements)

References 6 publications

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“…Our expression data suggest that the imprinted genetic program is still evident in the mature brain. The concept of an imprinted genetic pattern has been strengthened by the identification of genes that mark morphogenetic fields during brain development (24,25). The pattern of gene expression for a small set of genes for a particular brain region and its relatedness to patterns seen in other regions has been used extensively in developmental biology to help understand the embryologic origins and functional relationships between brain regions (2,26).…”

Section: Discussionmentioning

confidence: 99%

Adult mouse brain gene expression patterns bear an embryologic imprint

Zapala

Hovatta²,

Ellison³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

176

162

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The current model to explain the organization of the mammalian nervous system is based on studies of anatomy, embryology, and evolution. To further investigate the molecular organization of the adult mammalian brain, we have built a gene expression-based brain map. We measured gene expression patterns for 24 neural tissues covering the mouse central nervous system and found, surprisingly, that the adult brain bears a transcriptional ''imprint'' consistent with both embryological origins and classic evolutionary relationships. Embryonic cellular position along the anteriorposterior axis of the neural tube was shown to be closely associated with, and possibly a determinant of, the gene expression patterns in adult structures. We also observed a significant number of embryonic patterning and homeobox genes with region-specific expression in the adult nervous system. The relationships between global expression patterns for different anatomical regions and the nature of the observed region-specific genes suggest that the adult brain retains a degree of overall gene expression established during embryogenesis that is important for regional specificity and the functional relationships between regions in the adult. The complete collection of extensively annotated gene expression data along with data mining and visualization tools have been made available on a publicly accessible web site (www.barlow-lockhartbrainmapnimhgrant.org).database ͉ development ͉ evolution ͉ gene expression profiling ͉ inbred strains of mice T he adult nervous system achieves its mature form as the result of neuroectodermal cells committing to a specific fate and then segregating into distinct regional collectives of neurons that become fully functional through establishment of connections to other neurons. Our current understanding of brain architecture and organization is based on studies of embryology, anatomy, and evolution in which direct observation of anatomic structures was the foundation for postulated models of brain structure (1). Recent models of brain development and maturation consider relationships between different regions based on the expression of specific genes in assigning developmental origins of adult structures (2, 3). Here, we have constructed a regional gene expression atlas of the adult mouse brain and analyzed the quantitative results by using molecular classification algorithms.Genome-wide gene expression profiling is a powerful technique for deriving information about specific brain regions (4, 5). This approach has been used to measure gene expression patterns in particular regions, subregions, or cell populations in the brain (6-11). Two previous studies have analyzed gene expression differences across multiple regions of the mammalian brain by using multiple strains or species (12,13). However, the current study is the most extensive to date in terms of the number of genes and the coverage of different neural tissues. Our goal was to create a publicly accessible gene-based brain map with data sets, metadata, datab...

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Section: Discussionmentioning

confidence: 99%

Adult mouse brain gene expression patterns bear an embryologic imprint

Zapala

Hovatta²,

Ellison³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

176

162

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“…Chimeras are derived from more than one embryo; therefore, their body is formed of cells from different individuals, thus having different genetic constitutions. In transplantation chimeras, donor and host cells can be easily distinguished for they are morphologically different (22)(23)(24)(25)(26). With this method (grafting quail neural crest cells on chick embryos), Le Douarin demonstrated that neural crest cells do not contribute to the formation of pancreatic endocrine cells (27).…”

Section: Chimerasmentioning

confidence: 99%

Pancreatic Cell Lineage Analyses in Mice

Herrera

Népote

Delacour

2002

ENDO

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Pancreas Differentiation and MorphogenesisThe pancreas contains endocrine and exocrine cells. The exocrine pancreas represents more than 95% of the gland; it is composed of the acinar secretory cells, producing digestive enzymes such as amylase, and the excretory ducts. The endocrine cells of the pancreas form clusters embedded in the exocrine tissue: the islets of Langerhans. Islets are composed of four types of endocrine cells: the centrally located b cells produce insulin, while the peripheral a, d, and PP cells produce glucagon, somatostatin, and pancreatic polypeptide, respectively. Pancreas OrganogenesisThe pancreas initially develops from distinct dorsal and ventral primordia that later fuse to form the mature organ. This involves a sequential cascade of inductive events in association with the activation of specific transcription factors. Pancreatic buds evaginate from the early foregut endoderm caudally to the stomach primordium, near the prospective liver: the molecular determinants that define the position of the pancreas along the anterior-posterior axis remain unknown (1,2). The first hormone-containing cells found in early primordia are epithelial and appear located exclusively within the walls of the embryonic ducts or cords. Contrary to what is observed in adult islets, these cells frequently contain simultaneously more than one hormone; this has suggested the existence of a common precursor cell for all four islet cell types. For instance, because glucagon-containing cells are the first to differentiate in early buds, and given the presence of cells co-expressing glucagon and insulin, it was proposed that mature insulin cells derive from glucagon progenitors (3).Commitment to a pancreatic fate occurs as early as embryonic d 8-8.5 (E8-E8.5) in mice. Permissive signals released from adjacent mesodermal structures, including the notochord, aorta, and cardiac mesoderm, are important for induction of the pancreatic program. The notochord induces dorsal pancreas development through the inhibition of SHH (Sonic hedgehog) in pre-pancreatic dorsal endoderm. Shh is expressed in the early gut endoderm and has been shown to pattern it (1,(4)(5)(6). This Shh repression, which appears to be by activin bB and FGF2 (7), is permissive for the expression of Pdx1. Shh is also repressed, and Pdx1 expressed, in the ventral pre-pancreatic endoderm.It is intriguing that the same mesenchymal morphogens have opposite inductive effects on the dorsal and ventral pancreas: in the absence of dorsal mesoderm, the dorsal endoderm expresses liver markers, whereas, without ventral mesoderm (i.e., cardiac mesoderm and septum transversum), the ventral endoderm "defaults" to pancreas instead of liver. Indeed, signals from ventral mesoderm (FGFs) promote hepatic development (8).The first indication of morphogenesis occurs at E9.5, when the dorsal mesenchyme condenses and the underlying endoderm evaginates to form a recognizable dorsal pancreatic bud; the ventral bud appears one day later (E10.5). Both buds subsequently proliferate,...

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“…In Xenopus laevis, the neuroectoderm is induced on the dorsal side by signals such as noggin, chordin, follistatin, and Xnr3 emanating from the Spemann organizer during early gastrulation (4)(5)(6)(7)(8)(9). Although BMP4 has an inhibitory effect on ectoderm to differentiate into neuroectoderm (10), the blockade of the signal triggers the neuroectoderm formation (11)(12)(13).…”

mentioning

confidence: 99%

Xenopus Zic 3, a primary regulator both in neural and neural crest development

Nakata

Nagai

Aruga

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

233

190

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Xenopus Zic3 is a Xenopus homologue of mouse Zic and Drosophila pair-rule gene, odd-paired. We show here that Zic3 has significant roles both in neural and neural crest development in Xenopus embryo. Expression of Zic3 is first detected in prospective neural plate region at gastrulation. Onset of the expression was earlier than most proneural genes and followed chordin expression. The expression was induced by blockade of BMP4 signal. Overexpression of Zic3 resulted in hyperplastic neural and neural crest derived tissue. In animal cap explant, the overexpression of Zic3 induced expression of all the proneural genes and neural crest marker genes. These findings suggest that Zic3 can determine the ectodermal cell fate and promote the earliest step of neural and neural crest development.

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über Induktion von Embryonalanlagen durch Implantation artfremder Organisatoren

Cited by 496 publications

References 6 publications

Adult mouse brain gene expression patterns bear an embryologic imprint

Adult mouse brain gene expression patterns bear an embryologic imprint

Pancreatic Cell Lineage Analyses in Mice

Xenopus Zic 3, a primary regulator both in neural and neural crest development

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