2006 Fiscal Year Final Research Report Summary
Stem Cell Epigenetics by DNA Methylation Profile
| Project/Area Number |
16380226
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied molecular and cellular biology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TANAKA Satoshi The University of Tokyo, Graduate School of Agricultural and Life Sciences, Associate Professor, 大学院農学生命科学研究科, 助教授 (90242164)
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| Co-Investigator(Kenkyū-buntansha) |
SHIOTA Kunio The University of Tokyo, Graduate School of Agricultural and Life Sciences, Professor, 大学院農学生命科学研究科, 教授 (80196352)
HATTORI Naka The University of Tokyo, Graduate School of Agricultural and Life Sciences, Project Associate Professor, 大学院農学生命科学研究科, 特任助教授 (30270896)
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| Project Period (FY) |
2004 – 2006
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| Keywords | DNA methylation / TS cells / ES cells / Epigenetics / Histone modifications |
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| Research Abstract |
In mammalian genome, there are substantial numbers of tissue dependently and differentially methylated regions (T-DMRs) that are differentially methylated depending on type or differentiation status of the cells. Combinations of methylation/unmethylation of T-DMRs form "DNA methylation profile" of cells. In this study, we aimed to reveal DNA methylation profile common to all, or unique to each, of stem cells derived from early mouse embryos such as ES cells, TS cells and EG cells. By comparing DNA methylation profiles of these stem cells, by RLGS and computer-simulated RLGS, we could successfully identify multiple T-DMRs that are differentially methylated among stem cells examined. One of such T-DMRs, located at PRISM locus, was hypermethylated only in TS cells. Both ES and TS cells appeared not to express PRISM gene at undifferentiated state, but the gene was derepressed by a treatment with an inhibitor of histone deacetylase, TSA, suggesting that the PRISM gene is repressed by histone deacetylation in undifferentiated stem cells. Inhibitor of DNA methylation further increased derepressed PRISM expression in TS cells implying that the DNA methylation may ensure the repressed status in TS cells. We also analyzed role of DNA methylation in the regulation of Ddah2 gene in trophoblast cell lineage. Ddah2 gene was repressed in undifferentiated TS cells with 5 GpGs in its enhancer region highly methylated. Once the cells were induced to differentiate, methylation of the enhancer was decreased and the Ddah2 gene was upregulated. In vitro methylation of only the enhancer fragment was enough to inhibit not only the enhancer activity but also the activity of unmethylated promoter region, indicating a causal role of DNA methylation in silencing of Ddah2 gene.
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Research Products
(11 results)
