| Project/Area Number |
07680796
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Developmental biology
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
NISHIDA Hiroki Faculty of Bioscience and Biotechnology, TOKYO INSTITUTE OF TECHNOLOGY,Assoc.Prof., 生命理工学部, 助教授 (60192689)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1995: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Ascidian embryogenesis / endoderm differentiation / Alkaline phosphatase / Cytoplasmic determinant / gene expression / 原索動物 / ホヤ / 胚発生 / 発生運命 / 細胞質内決定因子 / 内胚葉 / 組織分化 |
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| Research Abstract |
Alkaline phosphatase (AP) activity is expressed in endodermal cells of ascidian larvae. It was reported previously that the expression of AP activity is resistant to treatment with actinomycin D,a transcription inhibitor. The resistance of AP expression to actinomycin D treatment suggests that appearance of AP activity does not depend on zygotic transcription and that its appearance is mediated by the translational activation of maternal AP mRNA present in ascidian eggs. To directly examine whether or not maternal AP transcripts are present in the cytoplasm of eggs, the endoderm-specific alkaline phosphatase was purified and its N-terminal amino acid sequence was determined in Halocynthia roretzi. Based on this sequence, we isolated a cDNA of this enzyme (HrES-AP) which is 3017-bp long and contains the complete open reading frame and polyadenvlic acid. HrES-AP exhibited a 52.6% homology to a non-specific mouse AP and is specificaly expressed in endoderm precursor cells of the tailbud embryos. As the results of northern blots and in situ hybridization, AP transcripts were not detected in the cytoplasm of unfertilized eggs and they were first detected at the neurula stage in endoderm precursor cells. These results indicate that at least in Halocynthia, embryonic AP activity exclusively depends on the activation of zygotic AP genes, presumably by cytoplasmic determinants present in eggs.
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