| Project/Area Number |
03454026
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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 |
動物発生・生理学
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| Research Institution | Waseda University |
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Principal Investigator |
YASUMASU Ikuo Waseda University, School of Education, Department of Biology, Professor, 教育学部, 教授 (10063421)
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| Project Period (FY) |
1991 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 1993: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1992: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1991: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | Sea Urchin Embryos / Micromere / Growth of Pseudopodial Cable / Spicule Rod Formation / Protein Kinase / Insulin / RNA Synthesis / Protein Phosphorylation / プロティンチロシンキナーゼ / GTP結合タンパク質 / 百日咳毒素 / プロテインチロシンキナ-ゼ |
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| Research Abstract |
Micromere-derived cells of sea urchin embryos are known to produce pseudopodial cables and spicule rods during culture with horse serum or blastocoelic fluid isolated from sea urchin embryos. In the present study, insulin was found to induce the cable growth without spicule rod formation. Insulin binding protein was found by SDS-PAGE of insulin treated cells. Insulin bound to the cells with Kd of about 0.5 pM and bound insulin was replaced by unknown compounds in horse serum and blastocoelic fluid. This indicates that horse serum and blastocoelic fluid contain insulin-like compounds. Insulin binding in the cells increased in 6 hr period due to translocation of the receptor protein from microsome to plasma membrane and was maintained high up to 40 hr of culture in the absence of horse serum or insulin. In the cells with high insulin binding capacity, insulin, as well as horse serum, augmentation of RNA synthesis occurred following activation of protein phosphorylation and finally resulted in the cable growth. Inhibition of protein phosphorylation reduced the rate of RNA synthesis and inhibition of RNA synthesis by actinomycin D after insulin-induced augmentation of protein phosphorylation resulted in blockage of pseudopodial cable grwoth. In the cells kept with horse serum, the rates of protein phosphorylation and RNA synthesis remained high even after the initiation of cable growth. Actinomycin D introduced after the cable growth initiation allowed the cells treated with horse serum or insulin to cause pseudopodial cables but blocked the spicule formation in horse serum-treated cells. Horse serum and blastocoelic fluid seems to contain signalling compounds other than insulin.
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