2005 Fiscal Year Final Research Report Summary
Molecular dissection of epigenetic transcriptional regulation of flower homeotic gene.
| Project/Area Number |
16370029
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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 |
植物生理・分子
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| Research Institution | Notional Institute of Agrobiological Sciences |
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Principal Investigator |
TAKATSUJI Hiroshi National Institute of Agrobiological Sciences, Plant Physiology Department, Developmental Biology Lab., Head, 生理機能研究グループ形態発生研究チーム, チーム長 (10360455)
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| Co-Investigator(Kenkyū-buntansha) |
TSUCHIMOTO Suguru Tokyo University, Institute of Molecular and Cellular Biosciences, Assistant professor, 分子細胞生物学研究所, 助手 (60212057)
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| Project Period (FY) |
2004 – 2005
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| Keywords | homeotic gene / epigenetic regulation / DNA methylation / siRNA / ectopic expression / gene silencing / curly leaf / MADS-box gene |
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| Research Abstract |
pMADS3 is a class C floral homeotic gene of petunia specifically expressed in stamens and carpels. Introduction of pMADS3 partial genomic sequence resulted in ectopic expression of endogenous pMADS3 (ect-pMADS3 phenotype) in some transgenic petunia lines, a novel epigenetic event. Inclusion of intron 2 (4 kb) in the transgene was essential to induce ect-pMADS3 phenotype. Some T1 individuals inherited the phenotype even after losing the transgene by segregation. We detected aberrant RNAs encoding sense- and antisense sequences of the intron II. These results suggested the involvement of RNA-directed DNA Methylation (RdDM) in the ect-pMADS3 phenomenon. To examine this possibility, we expressed an inverted repeat (IR) form of 1-kb sub-region of pMADS3 intron 2 (region II) and found that it induces ect-pMADS3 phenotype. We further dissected the region II by this strategy and found that a 300-bp sub-fragment was sufficient to induce the ect-pMADS3 expression. We also found that the DNA sequence in region II was methylated in the ect-pMADS3 lines, indicating a correlation between the DNA methylation and the pMADS3 ectopic expression. Therefore, it was strongly suggested that DNA methylation can lead to transcriptional activation。
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