Quantitative microscopic analysis of sister chromatid cohesion in mitosis

2015 Fiscal Year Final Research Report

• Project/Area Number: 26640086
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Tumor biology
• Research Institution: Japanese Foundation for Cancer Research
• Principal Investigator: Hirota Toru 公益財団法人がん研究会, がん研究所・実験病理部, 部長 (50421368)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 細胞分裂 / 染色体分配 / 姉妹染色分体 / コヒージョン / カテネーション / コヒーシン / コンデンシン / トポイソメラーゼ IIα

Outline of Final Research Achievements

The formation of mitotic chromosomes requires both compaction of chromatin and the resolution of replicated sister chromatids. Compaction occurs during prophase, depending on the activity of condensin II. Exactly when sister chromatid resolution occurs has been largely unknown, as has its molecular requirements. In this study, we visualized sister resolution by sequential replication labelling with two distinct nucleotide derivatives. Quantitative analyses allowed us to find that sister resolution starts already at the beginning of prophase, proceeds concomitantly with chromatin compaction and is largely completed by the end of prophase. Sister resolution was abolished by inhibition of topoisomerase IIα and by inactivation of condensin II, whereas blocking cohesin dissociation from chromosomes had little effect. Sister resolution is thus an intrinsic part of mitotic chromosome formation in prophase, and shares the molecular requirement for condensin II with prophase compaction.

Free Research Field

細胞生物学、染色体動態学