1991 Fiscal Year Final Research Report Summary
Studies on differentiation induced by cell-cell interaction with optical-image analysis - Intracellular mechanism of neural induction in the isolated cleavage-arrested blastomeres from the early Halocynthia embryo.
| Project/Area Number |
02404021
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | University of Tokyo |
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Principal Investigator |
TAKAHASHI Kunitaro Dept. Neurobiology, Inst. Brain Research, Faculty of Medicine, University of Tokyo, Professor, 医学部(医), 教授 (10010034)
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| Co-Investigator(Kenkyū-buntansha) |
OKADO Haruo Dept. Neurobiology, Inst. Brain Res., Faculty of Medicine, University of Tokyo,, 医学部(医), 助手 (60221842)
OKAMURA Yasushi Dept. Neurobiology, Inst. Brain Research, Faculty of Medicine, University of Tok, 医学部(医), 助手 (80201987)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Neural differentiation / Cell-cell interaction / [Ca^<2+>]_i / Tyrosine kinase receptor / Gap junction / Ion channels / Transcriptional regulation / Confocal microscopy |
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| Research Abstract |
The anterior-animal a_<4-2> blastomere isolated from the cleavage-arrested Halocynthia 8-cell embryo, which includes the presumptive neural domain, differentiated into epidermal type when cultured in isolation, but was Induced to differentiate into neural type when contacted with a presumptive notochordal A41 blastomere or treated with proteolytic enzymes. Using this simplified neuralinduction model, the image-analysis of Ca ion concentration with fluorescent probes and the quantitative analysis of the transcription and the expression of neural specific ion channels were performed in order to clarify the intracellular mechanisms of the induction. So far Ca ion concentration within the a_<4-l> blastomere showed no positive correlation with the induction. Both activators for A-kinase and C-kinase were applied on the isolated a_<4-1> blastomere but no indication of neural induction was found. However, basic FGF, an activator of tyrosine klnase receptors, did induce neural type differentiation. The down or up-regulation of the intercellular gap junction was found as a result of inductive neural or epidermal differentiation of the contacted two blastomeres respectively by optical measurement of the junctional permeability. The initiation periods of expression and transcription of Na channels and anomalous rectifier K channels were determined electrophysiologically or by RNAse protection assay with the cloned DNA probe. It was found that the transcription of the former initiated just after the induction and that of the latter was stopped at the time. In order to confirm above changes in the normal embryos the presumptive neural a_<4-2> and notochordal A_<4-1> blastomeres were injected with differently fluorescent cell-lineage markers respectively at the stage of 8-cell and the contact between two domains was observed at supposed induction period of the 64-cell stage with a confocal microscope.
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Research Products
(15 results)
