| Project/Area Number |
13680802
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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 | NIIGATA UNIVERSITY |
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Principal Investigator |
MAENO Mitsugu NIIGATA UNIVERSITY Faculty of Science, Associate Professor, 理学部, 助教授 (10190315)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2001: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | amphibia / embryonic blood cells / vascular endothelial cells / BMP-4 / FGF / organizer / induction / differentiation |
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| Research Abstract |
In order to determine the tissue interactions that propagate blood formation in amphibian embryogenesis, we used embryos that had the vegetal cytoplasm removed. These embryos displayed a marked enhancement of globin expression. Several lines of experimental evidence demonstrate the critical role of animal pole-derived ectoderm in blood cell formation: 1) Mesoderm derived from dorsal blastomeres injected with galactosidase mRNA (as a lineage tracer) expressed globin when interfaced with an animal pole-derived ectodermal layer: 2) Embryos in which the animal pole tissue had been removed by dissection at the blastula stage failed to express globin: 3) Exogastrulated embryos that lacked an interaction between the mesodermal and ectodermal layers failed to form blood cells, while, muscle cells were observed in these embryos. These observations suggest that default mesodermal cells need an additional BMP-4-dependent factor from the overlying ectoderm for further differentiation into a blood cell lineage.
Further experiments were done to elucidate the relationship between blood and vascular cell differentiation in the ventral blood island mesoderm. Using Xtie-2, as a vascular cell maker, it was shown that BMP (bone morphogenetic protein) signal is essential for both blood and vascular cell differentiation. On the other hand, FGF (fibroblast growth factor) signal was shown to control the distinct localization of vascular and blood cells. Therefore this study suggests that the early steps of blood and vascular cell differentiation are regulated by a common BMP-4-dependent signaling; however, distinct factor(s) such as FGF are involved in different distribution of these two cell lineages.
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