| Project/Area Number |
16K07456
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Genetics/Chromosome dynamics
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| Research Institution | Tokyo Metropolitan Institute of Medical Science |
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Principal Investigator |
FUKATSU Rino 公益財団法人東京都医学総合研究所, ゲノム医科学研究分野, 研究員 (70600419)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2018: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2017: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2016: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
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| Keywords | グアニン4重鎖 / Rif1 / 複製タイミング / 染色体高次構造 / 多量体化 / DNA結合 / HEATリピート / DNA複製 / グアニン４重鎖 / キナーゼ阻害剤 / グアニン四重鎖 / 染色体ループ / Rif1タンパク質 / 分裂酵母 / R-ループ |
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| Outline of Final Research Achievements |
A conserved nuclear factor, Rif1, is required for genome-wide regulation of origin firing timing. It represses origin firing through its ability to generate replication-repressive chromatin architecture and to recruit a phosphatase. It binds to G-quadruplex through its two G4 binding domain, one located in the N-terminal HEAT repeats and the other located near the C-terminus. It binds preferentially parallel-type, oligomerized G4. Both N-terminal HEAT repeats and the C-terminal unknown domain are required for origin suppression by Rif1. Genetic screening for a mutant that can bypass Cdc7(Hsk1) function led to identification of L848S and R236H that can no longer repress replication. L848S fails to bind to chromatin, but R236H still binds to chromatin. On the basis of the results, we have proposed a model on how multimeric Rif1 protein binds to multimeric G4 on the chromatin and tether chromatin fibers to generate a higher-order chromatin structure.
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| Academic Significance and Societal Importance of the Research Achievements |
核内クロマチン構造は、複製、転写、組換え、修復等染色体の維持や機能発現と密接に関連する。TAD(Topologically Associated Domain)は、発生、分化の過程での転写制御や、DNA複製の時空間制御に関連することが明らかとなっている。我々はRif1という核因子がこの過程の制御に重要な役割を果たすことを見出した。本研究により、Rif1による染色体高次構造形成における、G4の重要性、及び、関与するRif1上の機能ドメインが明らかとなった。本研究成果は、これまで未知であったG4の生物学的意義の一端を解明するとともに、G4-Rif1を用いた染色体高次構造の人為的操作の可能性を示す。
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