Concerted regulation of DNA replication, transcription, and repair by the conserved nuclear factor Rif1.

2017 Fiscal Year Final Research Report

• Project/Area Number: 26251004
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Molecular biology
• Research Institution: Tokyo Metropolitan Institute of Medical Science
• Principal Investigator: MASAI Hisao 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, 副所長 (40229349)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 複製タイミング / グアニン４重鎖 / クロマチンループ / 染色体高次構造 / 非相同末端結合 / Rif1タンパク質 / ES細胞 / 転写

Outline of Final Research Achievements

Rif1 is a conserved chromatin factor that regulates DNA replication, DNA repair and transcription. It may be involved in chromatin loop formation at nuclear periphery. We have determined genome-wide Rif1 bindings sites (Rif1BS) in fission yeast and identified a G-rich consensus sequence (Rif1CS). We then demonstrated the essential role of Rif1CS in chromatin binding of Rif1 and subsequent repression of DNA replication over a 100kb segment. Footprinting with DMS or various nucleases, polymerase stop assays as well as the effect of 7-deaza dGTP demonstrated that Rif1BS adopts G-quadruplex like structures. Purified fission yeast and mammalian Rif1 proteins specifically bind to this structure. Rif1 can simultaneously bind to multiple molecules of G4 through oligomerization, providing potential basis for its ability to tether multiple chromatin fibers to generate chromatin compartment that may coordinately regulate replication, transcription or repair.

Free Research Field

生化学