Analysis of adaptive mutation induced by epeigenetic mutation

• Project/Area Number: 18K19279
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 43:Biology at molecular to cellular levels, and related fields
• Research Institution: Hokkaido University
• Principal Investigator: Murakami Yota 北海道大学, 理学研究院, 教授 (20260622)
• Project Period (FY): 2018-06-29 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000); Fiscal Year 2019: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000); Fiscal Year 2018: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
• Keywords: エピジェネティクス / 適応戦略 / 突然変異 / ヘテロクロマチン / 環境適応 / 分裂酵母 / 適応

Outline of Final Research Achievements

Our group found that transcriptionally inactive heterochromatin is ectopically formed on the fission yeast genome, which alters cellular phenotype. Together with the recent report that suggest heterochromatin may increase mutation rate of genes embedded with heterochromatin, I hypothesize that gene repression induced by ectopic heterochromatin promote temporal adaptation and the adapted situation is fixed by the mutation induced by ectopic heterochromatin formation. To examine this hypothesis, I have been trying to establish the assay system that enable the measurement of mutation rate in the absence and presence of heterochromatin on the target gene. Though it took long time to establish the system, I finally establish it. Preliminary results suggest that heterochromatin indeed increase the spontaneous mutation rate.

Academic Significance and Societal Importance of the Research Achievements

この仮説は可塑性を持つエピジェネティックな変異によるトライアンドエラーによりまず一時的な適応をおこない、その後遺伝的変化によりその適応状態を固定するという、二段階適応機構を想定している。これは、適応戦略・進化戦略を考える上で新規・かつ重要な概念であり、生物進化の分野に大きなインパクトを与える。