| Project/Area Number |
16209033
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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 | Osaka University |
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Principal Investigator |
KANAKURA Yuzuru Osaka University, Graduate School of Medicine, Professor, 医学系研究科, 教授 (20177489)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMURA Itaru Osaka University, Graduate School of Medicine, Associate Professor, 医学系研究科, 助教授 (00294083)
MIZUKI Masao Osaka University, Graduate School of Medicine, Lecturer, 医学系研究科, 講師 (80283761)
SHIBAYAMA Hirohiko Osaka University, Graduate School of Medicine, Assistant, 医学系研究科, 助手 (60346202)
菅原 浩之 大阪大学, 医学系研究科, 助手 (40362701)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥45,630,000 (Direct Cost: ¥35,100,000、Indirect Cost: ¥10,530,000)
Fiscal Year 2005: ¥16,640,000 (Direct Cost: ¥12,800,000、Indirect Cost: ¥3,840,000)
Fiscal Year 2004: ¥28,990,000 (Direct Cost: ¥22,300,000、Indirect Cost: ¥6,690,000)
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| Keywords | FLT3 / Notch / HOXB4 / Anamorsin / c-myc / hematopoietic Stem Cell / apoptosis / アナモルシン / 増殖 / 分化 / 造血器腫瘍 |
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| Research Abstract |
1.To explore activation mechanism of FLT3 TKD mutation, we analysed critical tyrosine residues for the constitutive activation and downstream signaling of the mutant by generating a series of single Tyr→Phe substitution mutant of all 22 cytoplasmic tyrosine residues of murine FLT3 TKD-mutant (mFLT3Asp838Val). Tyr845Phe, Tyr892Phe and Tyr922Phe substitutions suppressed the phosphorylation of mFLT3Asp838Val itself, the activation of Erk1/2,STAT3 and STAT5, and the factor-independent cell proliferation and survival. In contrast, these three Tyr→Phe mutations partially suppressed but maintained the ligand-dependent activation and anti-apoptotic activity of wild-type FLT3, suggesting that these tyrosine residues were more critical for the constitutive activation and signaling of mFLT3Asp838Val.
2.We examined the expression of cell cycle regulatory molecules during Notch- and HOXB4-induced self-renewal of hematopoietic stem cells, and found that both molecules induce the expression of c-myc.
… More
In addition, we determined that HOXB4 activated the c-my promoter through the element between -195 and -161 bp. We also proved that the induction of c-myc activity alone was sufficient for enhancing self-renewal of hematopoietic stem cells in the presence of appropriate cytokines using Myc/ERT, which reveals c-myc activity in response to 4-hydroxytamoxifen. These results indicated that Notch and HOXB4 induce self-renewal of hematopoietic stem cells through the induction of c-myc.
3.We generated knock out mice for Anamorsin. Anamorsin^<-/-> mice are embryonic lethal due to the failure of definitive hematopoiesis in the fetal liver, Although the number of hematopoietic stem/progenitor cells in the fetal liver did not decrease in these mice, myeloid and particularly erythroid colony formation was severely disrupted. Also, Anamorsin^<-/-> erythroid cells initiated apoptosis during terminal maturation. As for the mechanism of Anamorsin-mediated cell survival, a microarray analysis revealed that the expression of Bcl-xL and Jak2 was severely impaired in the fetal liver of Anamorsin^<-/-> mice. Less
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