| Project/Area Number |
17209036
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Hematology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
NAKAUCHI Hiromitsu The University of Tokyo, Institute of Medical Science, Professor, 医科学研究所, 教授 (40175485)
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| Co-Investigator(Kenkyū-buntansha) |
EMA Hideo The University of Tokyo, Institute of Medical Science, Project Associate Professor, 医科学研究所, 産学官連携研究員(特任助教授) (50344445)
ETO Koji The University of Tokyo, Institute of Medical Science, Assistant Professor, 医科学研究所, 助手 (50286986)
KAMIYA Akihide The University of Tokyo, Institute of Medical Science, Assistant Professor, 医科学研究所, 助手 (30321904)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥52,260,000 (Direct Cost: ¥40,200,000、Indirect Cost: ¥12,060,000)
Fiscal Year 2006: ¥20,020,000 (Direct Cost: ¥15,400,000、Indirect Cost: ¥4,620,000)
Fiscal Year 2005: ¥32,240,000 (Direct Cost: ¥24,800,000、Indirect Cost: ¥7,440,000)
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| Keywords | hematopoietic stem cells / asymmetric division / DNA methylation / self-renewal / commitment / DNAメチル化酵素 / Dnmt3a / Dnmt3b |
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| Research Abstract |
Stem cells are defined as cells with multilineage differentiation and self-renewal potentials. These cells play a crucial role in the development, regeneration, and maintenance of tissues and organs. Since mouse hematopoietic stem cells (HSCs) could be highly purified, we analyzed their differentiation manner at the clonal level. Using mouse HSCs as an adult stem cell model, we attempted to clarify the molecular basis underlying self-renewal and lineage commitment in stem cells. Moreover, we sought a regulatory mechanism in common with other adult stem cells. We successfully established a sensitive single-cell reconstitution assay by using compromised bone marrow cells as rescue cells for lethally irradiated mice. Using this method, differentiation potentials in paired daughter cells should be clarified in more detail. We also successfully developed a single-cell immunostaining method to quantitatively detect intracellular molecules in HSCs. Using this method, we were able to show intracellular mobilization and phosphorylation of signal molecules. We tried to detect transcription factors, DNA transmethylases, polycomb group molecules that would be unevenly distributed between paired daughter cells. However, so far we have not found such molecules. On the other hand, we showed that either Dnmt3a or Dnmt3b is essential for self-renewal in HSCs. Interestingly, neither Dnmt3 nor Dnmt3b was shown to be necessary for multilineage differentiation in HSCs. We analyzed hepatic stem cells isolated from mouse fetal liver. Over-expression of a dominant negative form of Tcf-4 inhibited both self-renewal and differentiation/maturation in hepatic stem cells.
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