Toward manual control of the initiation of homologous recombination for genome diversification

2014 Fiscal Year Final Research Report

• Project/Area Number: 22247002
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Genetics/Genome dynamics
• Research Institution: The Institute of Physical and Chemical Research
• Principal Investigator: SHIBATA Takehiko 独立行政法人理化学研究所, その他部局等, 研究員 (70087550)
• Co-Investigator(Kenkyū-buntansha): MIKAWA Tsutomu 理化学研究所, 生命システム研究センター, 専任研究員 (20321820) ; KUSANO Kohji 明治大学, 研究知財戦略機構, 研究推進員(客員研究員) (70336098) ; ARAI Naoto 日本大学, 生物資源科学部, 講師 (70297795)
• Project Period (FY): 2010-04-01 – 2015-03-31
• Keywords: ゲノム構築 / ゲノム再編 / ゲノム維持 / 遺伝的多様化 / 二本鎖切断修復 / 経路選択 / RecA/Rad51

Outline of Final Research Achievements

Homologous DNA recombination (HR) is regulated by double-strand DNA-break (DSB) formation and recombination-pathway choice among two types of HR (non-crossing-over and crossing-over) and non-homologous end-joining (NHEJ). (1) Using new bio-assays, we identified rice and Arabidopsis SPO11s (meiotic recombination-initiating proteins) and their intrinsic DSB-forming activity for the first time. (2) We identified using a newly devised genetic assay, DSB-repair pathway-choice functions of Srs2 helicase, which forms an active complex with Rad51 (a eukaryotic RecA-family recombinase). (3) We unexpectedly found that Rad51 functions in end-joining fidelity of the canonical NHEJ. (4) We revealed by structural and biochemical studies, roles of an acidic residue on a flexible loop of RecA in selecting ssDNA in its various in vitro functions, and in activation and inactivation of its recombinase activity. These results suggest new roles of RecA/Rad51 in all the three major DSB-repair pathways.

Free Research Field

生化学、遺伝学、タンパク質構造科学