| Project/Area Number |
15591079
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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 |
Pediatrics
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| Research Institution | Hirosaki University |
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Principal Investigator |
TOKI Tsutomu Hirosaki University, School of Medicine, Lecturer, 医学部, 講師 (50195731)
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| Co-Investigator(Kenkyū-buntansha) |
ITO Etsuro Hirosaki University, School of Medicine, Professor, 医学部, 教授 (20168339)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2003: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Transcription factor / Megakaryocyte / BACH1 / NF-E2 |
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| Research Abstract |
Object
Approximately 10% of newborn babies with Down's syndrome (DS) are born with a leukemoid reaction commonly called transient myeloproliferative disorder (TMD). A portion of DS patients will develop malignant acute megakaryoblastic leukemia (AMKL) during their first 4 years of life. The human BACH1 gene is localized to chromosome 21q22.1 within the potential DS-associated gene region. We have three objects in this research. First, disclosing the mechanism of the thrombocytopenia caused by the over-expression of transcription factor BACH1 in transgenic mice. Second, finding the target genes of BACH1 by excessive expression of the transcription factor. Third, investigating the contribution of BACH1 gene in developing TMD and AMKL in DS patients.
Results
Electron microscopic analysis of megakaryocytes derived from BACH1 transgenic mice revealed remarkable impairment of demarcation membrane and alpha-granule formation, the vacuolation of mitochondria, and the lower degree of heterochromat
… More
in content in nuclei. To investigate the proliferative ability of the megakaryocytic progenitor cells, we performed CFU-Meg colony formation assay. But, no difference was detected between transgenic and wild mice. These results suggest that the terminal differentiation and maturation process were impaired in the transgenic mouse megakaryocytes.
Using megakaryocytes developed in vitro culture of liver cells from 13 d. p. c. mouse fetuses in the presence of thrombopoietin, we examined some gene expression. The results of the assay showed the down-regulation of the beta1-tubulin and thromboxane A synthase (TXAS) gene. We also recognized the binding of BACH1 protein to the regulatory elements of TXAS gene by chromatin immunoprecipitation method. These results suggest that BACH1 regulates the megakaryocytic differentiation and maturation by antagonizing the p45NF-E2 activity.
At present, to investigate the function of BACH1 in leukemic cells, we succeeded in establishment of BACH1 overexpressing leukemic cell line by the gene transfection. Less
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