| Project/Area Number |
12480206
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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 |
Molecular biology
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| Research Institution | St. Marianna University School of Medicine |
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Principal Investigator |
NAKAJIMA Toshihiro St. Marianna University School of Medicine Department of Genome Science, Institute of Medical Science, Associate Professor, 難病治療研究センター, 助教授 (90260752)
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| Co-Investigator(Kenkyū-buntansha) |
FUKAMIZU Akiyoshi Tsukuba University, Professor, 応用生物化学系, 教授 (60199172)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥9,900,000 (Direct Cost: ¥9,900,000)
Fiscal Year 2002: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2001: ¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2000: ¥3,900,000 (Direct Cost: ¥3,900,000)
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| Keywords | transcriptional activation / acetylation / CREB binding protein (CBP) / transcriptional coactivator / RNAhelicase A(RHA) / DNA methylation / epigenetics / 転写抑制 / エピジェネチックス / RNAヘリケースA / DNA修飾 / メチル化 / ATPase / ヘリケース / HIVウイルス / RNAポリメラーゼII / 細胞内局在 / 転写後調節 / アセチル基転移酵素 / CREB結合タンパク質 / 転写活性化領域 |
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| Research Abstract |
In the eukaryotic gene expression, recruitment of the basal transcriptional machinery including RNA polymerase (Pol) II is a principle mechanism for transcriptional activation. A specific transcriptional factor interacts with components of this machinery and localizes them to a specific promoter. For example, cAMP responsive element binding protein (CREB) stimulates target gene expression by recruitment of CREB binding protein (CBP). CBP interacting phosphorylated CREB activates the transcription via two mechanisms. One is dependent on the histone acetyltransferase activity (HAT), another is recruitment of Pol II mediated by RNA helicase A (RHA). RHA is a member of the DExH family of ATPases / helicases and catalyzes the displacement of both double-stranded RNA and DNA from 3' to 5'. We found that RHA recruits Pol II to breast cancer specific tumor suppressor protein (BRCA1) and enhance HIV virus gene expression.
For further an understanding of the role of RHA on gene expression, we have identified a 50 amino acid transactivation domain that interacts with Pol II and termed it the minimal transactivation domain (MTAD) in this project. The protein sequence of this region contains six hydrophobic residues and is unique to RHA homologues and well conserved. A mutant with this region deleted from full-length RHA decreased transcriptional activity in CREB-dependent transcription. In addition, mutational analyses revealed that several tryptophan residues in MTAD are important for the interaction with Pol II and transactivation. These results suggest that RHA could independently regulate CREB-dependent transcription either through recruitment of Pol II or ATP dependent mechanisms.
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