1993 Fiscal Year Final Research Report Summary
Studies on neural-inducing actions of bFGF to Xenopus ectoderm cells and their intra-cellular signal transduction mechanisms.
| Project/Area Number |
04454135
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Neurophysiology and muscle physiology
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| Research Institution | University of Tokyo |
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Principal Investigator |
OKAMOTO Harumasa Univ.Tokyo, Fac.Med., Assoc.Prof., 医学部・(医), 助教授 (40134283)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Kunitaro Univ.Tokyo, Fac.Med., Professor, 医学部・(医), 教授 (10010034)
KENGAKU Mineko Univ.Tokyo, Fac.Med., DC fellow of Japanese Society for the Promotion of Science, 医学部・(医), 日本学術振興会特別研
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| Project Period (FY) |
1992 – 1993
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| Keywords | Neural induction / bFGF / Signal transduction / Xenopus laevis / Protein kinase C / Staurosporin |
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| Research Abstract |
The vertebrate nervous system is initially induced from a section of dorsal ectoderm by signal(s) from the underlying dorsal mesoderm during gastrulation. In an effort to identify the neural inducing factor(s) emanating from the dorsal mesoderm, we have examined the inductive action of various growth factors by applying them to ectoderm cells from Xenopus gastrulae (8 to 12.5-hour age) in a microculture system that we have recently established. Monoclonal antibodies that specifically recognize cellular differentiation antigens from three distinct ectoderm lineages (N1 for CNS neurons from neural tube, Me1 for melanophores from neural crest and E3 for skin epidermal cells from epidermal lineages, respectively) were used as markers to monitor the differentiation of cultured ectoderm cells.
We found that basic fibroblast growth factor (bFGF) was capable of specifically and reproducibly inducing gastrula ectoderm cells to produce CNS neurons and melanophores at physiological concentrations as low as 5 to 25pM.The induction of neural lineages by bFGF was accompanied more-or-less with the suppression of epidermal differentiation.
The response of ectoderm cells to bFGF changed dramatically during gastrulation. Ectoderm cells from early (8 to 9-hour) gastrula gave rise to CNS neurons, but yielded few melanophores. As ectoderm cells were prepared from gastrulae of increasing age, their competence to form neurons was gradually lost, whereas the production of melanophores was enhanced and peaked in 11-hour gastrula. The ability to form both neurons and melanophores was substantially reduced in 12.5-hour gastrula. Further we showed that staurosporin, a potent inhibitor of protein kinase C, suppressed does-dependently both bFGF- and mesoderm-induced differentiation of melanophores, whereas it did not affect the differentiation of CNS neurons, indicating differential signal transdusing pathways in neural tube and neural crest inductions.
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