Über die Determination der larvalen Organe und der Imaginalanlage bei Seeigeln

Ubisch, L. v.

doi:10.1007/bf02110964

Cited by 48 publications

(14 citation statements)

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“…Animal hemispheres (presumptive ectoderm) (12) and animal mesomere pairs isolated from 16-cell embryos (13) that are cultured in the presence of LiCl form spicules and guts, structures normally derived only from vegetal cells. Increasing LiCl concentration induces correspondingly increased levels of expression of vegetal molecular markers, which mimics the effect of transplantation of vegetal cells to the animal pole of cleaving embryos.…”

mentioning

confidence: 99%

SpFGFR, a New Member of the Fibroblast Growth Factor Receptor Family, Is Developmentally Regulated during Early Sea Urchin Development

McCoon

Angerer

1996

Journal of Biological Chemistry

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We describe the cloning of a new fibroblast growth factor receptor, SpFGFR1, that is differentially regulated at the level of transcript abundance during sea urchin embryogenesis. Sequence representing the conserved tyrosine kinase domain was obtained by reverse transcription-polymerase chain reaction using degenerate primers, and the entire open reading frame was obtained by standard cDNA library screening methods. SpFGFR contains a series of domains characteristic of FGFRs: three immunoglobulin-like motifs, an acid box, a transmembrane domain, a relatively long juxtamembrane sequence, a split tyrosine kinase domain, and two conserved intracellular tyrosine residues. Alternative splicing of SpFGFR generates two variants (Ig3L and Ig3S), which differ by insertion in the center of the Ig3 domain of 34 extra amino acids, encoded by an additional exon. Transcripts encoding both variants accumulate when morphogenesis begins with mesenchyme cell ingression and gastrulation. SpFGFR transcripts accumulate in all cell types of the embryo, although in situ hybridization shows that they are somewhat enriched in cells of oral ectoderm and endoderm. Transcripts encoding the Ig3S variant, whose structure resembles more closely that of vertebrate receptors, are enriched in endomesoderm, suggesting that the SpFGFR variants could play distinct roles in the sea urchin embryo.Cell-cell interactions are important in specifying cell fates in all embryos. Receptor-ligand combinations that activate signal transduction pathways are known mediators of these interactions in some cases and obvious candidates for signaling in others. Cell fate specification in sea urchin embryos is highly dependent on cell-cell interactions (reviewed in Refs. 1 and 2). For example, signaling among different blastomeres is known to begin during early cleavage since the developmental fates of tiers of early blastomeres are altered both by isolation and by transplantation into different signaling environments (3-6). Maintenance of positional information also requires continued signaling through blastula stage and, for determination of endodermal and secondary mesenchymal lineages, through early gastrula stages (7-9). In addition to positive inductive influences, signals sent from primary mesenchyme cells prevent pluripotent secondary mesenchyme cells from converting to a skeletogenic fate at the late gastrula stage (10), and unidentified signals repress expression of vegetal markers (11).The effect of LiCl on sea urchin development suggests the kinds of pathways that might mediate cell-cell interactions required to specify blastomere fates. Animal hemispheres (presumptive ectoderm) (12) and animal mesomere pairs isolated from 16-cell embryos (13) that are cultured in the presence of LiCl form spicules and guts, structures normally derived only from vegetal cells. Increasing LiCl concentration induces correspondingly increased levels of expression of vegetal molecular markers, which mimics the effect of transplantation of vegetal cells to the animal pole of c...

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mentioning

confidence: 99%

SpFGFR, a New Member of the Fibroblast Growth Factor Receptor Family, Is Developmentally Regulated during Early Sea Urchin Development

McCoon

Angerer

1996

Journal of Biological Chemistry

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“…Such embryos are said to be "vegetalized" (4). Von Ubisch (5) reported in 1929 that treatment of the separated animal hemisphere with LiCl resulted in the subsequent formation of guts and spicules by these blastomeres. This result suggests that the capability to form vegetal structures also resides in the animal blastomeres, but in a suppressed or inactive form, and that LiCl may somehow allow vegetal structures to form in blastomeres that have an otherwise quite different determination and fate.…”

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confidence: 99%

Lithium evokes expression of vegetal-specific molecules in the animal blastomeres of sea urchin embryos.

Livingston

Wilt

1989

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

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The mechanism of determination of early embryonic cells has been investigated using sea urchin embryos. An efficacious method of isolating blastomere pairs from the animal or vegetal halfof sea urchin embryos was developed. The overt differentiation of separated animal and vegetal blastomere pairs resembles that of separated animal and vegetal hemispheres isolated by manual dissection. Treatment of animal blastomeres with LiCl caused them to display a morphology resembling that of isolated vegetal blastomeres. The effects of separation of animal and vegetal blastomeres and of treatment of animal blastomeres with LiCl were examined at the molecular level using gut alkaline phosphatase and a spicule matrix protein RNA as markers of differentiation. Histochemical staining and in situ hybridization studies showed that these markers are normally only expressed in vegetal blastomeres but that their expression can be evoked in animal blastomeres by treatment with LiCl.The mechanisms of determination of early embryonic cells are a problem of fundamental importance in biology. Classical studies have shown that the animal and vegetal halves of very early sea urchin embryos are already determined; when separated, the two halves follow widely divergent paths of differentiation. Separated animal halves form hollow epithelial spheres with exaggerated cilia and little overt differentiation. Vegetal halves are able to form more normal embryos with archenterons, skeletal spicules, and pigment cells, which will occasionally go on to form a rather normal pluteus larvae (for reviews, see refs. 1-3).Treatment of embryos with a variety of agents, including LiCl, results in a pattern of differentiation in which archenterons are exaggerated (and/or exogastrulated), and the surface epithelium is reduced. Such embryos are said to be "vegetalized" (4). Von Ubisch (5) reported in 1929 that treatment of the separated animal hemisphere with LiCl resulted in the subsequent formation of guts and spicules by these blastomeres. This result suggests that the capability to form vegetal structures also resides in the animal blastomeres, but in a suppressed or inactive form, and that LiCl may somehow allow vegetal structures to form in blastomeres that have an otherwise quite different determination and fate.LiCI has also been shown to affect cell fate and pattern formation in amphibians (6, 7), suggesting that it alters a cellular process important in determination of cell fate in developing systems. Although LiCl may affect a variety of cellular processes, recent studies showing that LiCl has specific effects on secondary-messenger pathways in several different cell types (8-10) have stimulated our interest in perturbations caused by lithium.We have devised a simple method to study isolated blastomeres in culture that allows one to study the mechanisms of cell determination. The old finding that LiCl may respecify blastomere fate has been confirmed. In addition, we have shown that LiCl not only elicits vegetal structures in animal blastome...

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“…Furthermore, it has been shown that embryos derived only from animal cap mesomeres that once received appropriate induction from the micromeres developed into juveniles (Minokawa & Amemiya 1999). Animal caps treated with LiCl also had the potential to develop into pluteus‐like larvae (von Ubisch 1929). However, the potential of the pluteus‐like larvae derived from the LiCl‐treated animal caps to metamorphose into juveniles is yet to be examined.…”

Section: Discussionmentioning

confidence: 99%

“…After various intervals, the embryos were rinsed with JSW and then cultured in plastic Petri dishes filled with JSW. Isolated animal caps were treated with LiCl at an appropriate concentration immediately after isolation for 2 h as reported for indirect developers (von Ubisch 1929) and then rinsed with JSW. Occasionally, unfertilized eggs were treated with LiCl for 2 h, rinsed with JSW and fertilized.…”

Section: Treatment Of Embryos With Liclmentioning

confidence: 99%

“…The animal half (animal cap), which consists of eight mesomeres in 16‐cell stage embryos, exclusively develops into ectoderm, regardless of whether it is within embryos or is cultured in isolation (Horstadius 1975). Animal caps cultured in isolation with LiCl developed into pluteus‐like larvae as a result of the vegetalizing effect of LiCl (von Ubisch 1929). LiCl is therefore a useful tool for the analysis of regulating potential along the animal–vegetal axis in echinoid embryos.…”

Section: Introductionmentioning

confidence: 99%

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Regulating potential in development of a direct developing echinoid, Peronella japonica

Kitazawa

Amemiya

2001

Dev Growth Differ

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The regulating potential along the animal-vegetal axis of a direct developing echinoid, Peronella japonica, was investigated using LiCl. Animal caps isolated from 16-cell stage P. japonica embryos developed to permanent blastulae with an amniotic cavity. Treatment of animal caps with LiCl induced them to vegetalize with differentiation of the endoderm and subsequently develop into pluteus-like larvae. The larvae derived from the LiCl-treated animal caps were able to metamorphose and establish an adult body plan. A considerable fraction of whole embryos treated with LiCl exogastrulated and/or evaginated an amniotic cavity. The timing of the sensitivity to LiCl-mediated induction of evagination of the amniotic cavity was earlier than that for exogastrulation. Peronella japonica embryos became sensitive to LiCl induction of exogastrulation later than embryos of indirect developers. Some larvae with evaginated archenteron and/or evaginated amniotic cavity had metamorphic potential. These results suggest that LiCl can induce both vegetalization and evagination of invaginating structures. The present study is the first to show the potential of the presumptive ectoderm region to regulate the establishment of the adult body plan without any influence from other blastomeres, revealing that the regulating potential of sea urchin embryos is much larger than previously thought.

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Über die Determination der larvalen Organe und der Imaginalanlage bei Seeigeln

Cited by 48 publications

References 10 publications

SpFGFR, a New Member of the Fibroblast Growth Factor Receptor Family, Is Developmentally Regulated during Early Sea Urchin Development

SpFGFR, a New Member of the Fibroblast Growth Factor Receptor Family, Is Developmentally Regulated during Early Sea Urchin Development

Lithium evokes expression of vegetal-specific molecules in the animal blastomeres of sea urchin embryos.

Regulating potential in development of a direct developing echinoid, Peronella japonica

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