| Project/Area Number |
11670980
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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 |
Hematology
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| Research Institution | University of Tokyo Hospital |
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Principal Investigator |
CHIBA Shigeru University of Tokyo Hospital, Internal Medicine, Assistant Professor, 医学部・附属病院, 助手 (60212049)
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| Co-Investigator(Kenkyū-buntansha) |
KUROKAWA Mineo University of Tokyo Hospital, Internal Medicine, Assistant Professor, 医学部・附属病院, 助手 (80312320)
OGAWA Seishi University of Tokyo Hospital, Internal Medicine, Assistant Professor, 医学部・附属病院, 助手 (60292900)
HIRAI Hisamaru University of Tokyo Hospital, Internal Medicine, Assistant Professor, 医学部・附属病院, 助教授 (90181130)
KUMANO Keiki University of Tokyo Hospital, Internal Medicine, Research Staff, 医学部・附属病院, 助手
TAKAHASHI Tokiharu University of Tokyo Hospital, Internal Medicine, Assistant Professor, 医学部・附属病院, 助手 (30313125)
本田 浩章 東京大学, 医学部附属病院, 助手 (40245064)
三谷 絹子 東京大学, 医学部附属病院, 助手 (50251244)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2000: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Notch / signal / cleavage / phosphorylation / hematopoiesis / differentiation inhibition / GATA2 / Notchリガンド / DSL蛋白質 / 分化抑制 |
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| Research Abstract |
[Purpose] Aims of this study were to understand (1) how the signal through the Notch receptor is generated and (2) the mechanism of Notch-induced inhibition of differentiation in hematopoietic cells.
[Methods](1) Cleavage, translocation and phosphorylation of the Notch2 molecule were studied using specific antibodies against Notch2.(2) Effect of activated form of Notch1 (aN1) on differentiation of hematopoietic cells was studied. Next, changes in expression of hematopoietic transcription factors (HTF), which were involved in the differentiation and growth of hematopoietic cells, were examined. Finally, dominant-negative form of GATA (DN-GATA) and PU.1 were expressed in a cell line expressing aN1, and the resulting trasnfectants were used to study the response to differentiation stimulation.
[Results and Discussions](1-1) The transmembrane subunit of the Notch2 molecule was cleaved. Resulting molecules comprising the intracellular region were then shortly entered the nucleus.(1-2) The tra
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nslocated Notch2 molectules were phosphorylated.(1-3) Notch ligands initiated transcriptional control in the tarxet cells.(2-1) all inhibited mveloid and erythroid differentiation.(2-2) Expression level of various HTF was changed by the differentiation stimulation and such changes were not modified by aN1 in all the HTF except for GATA2. The expression level of GATA2 was decreased when wild-type 32D cells differentiate responding to G-CSF, while it was maintained when aN1 was introduced into 32D (aN1/32D). Further exogenous expression of DN-GATA or PU.1, which is known to block the function of GATA factors, reverted the aN1-induced differentiation block. These results indicated that aN1 blocks differentiation of hematopoietic cells through sustaining the expression level and function of GATA2.
[Conclusion] We revealed a part of mechanisms of initiation of Notch signaling. Activation of Notch blocks differentiation of hematopoietic cells, through sustaining the expression level and function of GATA2. Less
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