Why do eukaryotes have linear chromosomes?

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K19208
• 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: The University of Tokyo
• Principal Investigator: Kanoh Junko 東京大学, 大学院総合文化研究科, 教授 (10323809)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 染色体 / テロメア / 真核生物 / 原核生物 / 進化

Outline of Final Research Achievements

Generally, the chromosomes of eukaryotes such as yeasts are linear, while those of prokaryotic organisms such as Escherichia coli are circular. To elucidate why these two types of morphologies exist in the biological world and why eukaryotes do not possess circular chromosomes, we created cells with self-circularized chromosomes using fission yeast, which only has three chromosomes, and extensively analyzed their phenotype. As a result, it was found that cells with circular chromosomes tend to have tangled chromosomes during cell division, which leads to increased susceptibility to cell death. Furthermore, their high sensitivity to topoisomerase inhibitors suggests that topoisomerases may not function adequately on circular DNA in eukaryotic organisms.

Free Research Field

分子生物学

Academic Significance and Societal Importance of the Research Achievements

真核生物と原核生物は同じ祖先から進化したと考えられるが、染色体の形態が決定的に異なる。本研究の成果はこの生命の根源に迫るものであり、多くの人の関心を引き寄せるであろう。また、ヒトの癌の一種に環状染色体を含むものがある。本研究によって、環状染色体をもつ真核生物が正常に増殖することができるように操作することができれば、その癌の治療にも役立つ可能性が期待される。