Elucidation of chromosome structure by DNA multi-color imaging using super-resolution microscopy in living cells

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H06212
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Applied molecular and cellular biology
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Hideaki Takata 国立研究開発法人産業技術総合研究所, 生命工学領域, 主任研究員 (20455207)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 染色体 / クロマチン / イメージング / カルシウム / リン酸化

Outline of Final Research Achievements

To elucidate the mechanism of chromosome condensation during mitosis, chromatin imaging techniques including FLIM-FRET, super-resolution microscopy, and CRISPR/dCas9 system were employed. As a result, the function of a divalent cation, calcium ion, was revealed as a booster of chromosome condensation after nuclear envelope breakdown. In addition to the calcium ion, KIF4A which is localized at chromosome scaffold, an axial structure observed in the center of sister chromatids, is required for chromosome condensation during early mitosis. The phosphorylation site of KIF4A by Cdk1 was identified, and the phosphorylation was found to be required for the interaction with condensin I complex, which is also localized at chromosome scaffold and induces chromosome condensation by chromatin loop formation. The changes in chromatin structure in cancer cells and senescence cells were also detected using a CRISPR/dCas9 system.

Free Research Field

分子細胞生物学

Academic Significance and Societal Importance of the Research Achievements

本研究により、分裂期における染色体凝縮には蛋白質だけでなくカルシウムイオンの働きも必要であることを示した。このため、細胞内カルシウムイオン制御に関わる遺伝子異常が染色体異常につながる可能性が考えられる。また、KIF4AのCdk1によるリン酸化が染色体凝縮を開始するカギの一つであることを示し、分裂期初期の染色体凝縮機構の解明が進んだ。さらに、本研究で構築したCRISP/dCas9システムを活用することで、細胞状態変化に伴うクロマチン構造変化と遺伝子発現変化との関連を調べることで、将来的に生命現象の理解や疾患モニタリングへの応用等が期待できる。