研究課題
Various types of DNA damage can induce activation of dormant replication origins. Previously, it has been demonstrated that a single irrepairable double-strand break (DSB) formation can locally trigger dormant origin firing (Doksani et al., Cell, 2009). In this study, I aim at elucidating the mechanisms leading to dormant origin firing following DSB formation.I found that DNA damage checkpoints do not counteract DSB-induced dormant origin firing but the dormant origin firing activities are counteracted by histone acetylation state. While screening for other possible candidates that may contribute to DSB-induced dormant origin firing, I identified that telomere-related proteins, Rif1 and Ku complex, control the activation of dormant origins even in the absence of DSB. Interestingly, I found that Rif1 and yKu70 bind preferentially at regions between dormant origins and DSB site but not at regions downstream of DSB site. However, the binding profiles of Rif1 and yKu70 at those regions are not affected by DSB formation.Although there are still no evidences that Rif1 or yKu70 directly involved in DSB-induced dormant origin firing, the binding profiles of Rif1 and yKu70 closed to the MAT locus (DSB site) may hint an important role of Rif1 or yKu70 in controlling dormant origin near DSB site. I speculated that following DSB formation, yKu70 binds to the break site and may recruit an unknown factor. The unknown factor may then act on Rif1 and prevent its inhibitory activity of dormant origin firing. Further works will be needed to prove this hypothesis.
2: おおむね順調に進展している
Research results are not as significant as originally planned.
1. Determine whether DSB-induced dormant origin activation is a global response to DNA damage or a local phenomenon transmitted in cis to the lesion by checking whether ARS313 and ARS314 dormant origins can still fire when the DSB is induced on another chromosome.2. Bioinformatic analysis of ChIP-seq results of Rif1 binding profile either in the presence or absence of DSB formation.3. Repeat ChIP-seq analysis with yKu70 and compare the yKu70 binding profiles with the Rif1 binding profiles.
研究成果の一部については 東京都医学総合研究所 ゲノム医科学研究分野 ゲノム動態プロジェクトのホームページ（http://www.igakuken.or.jp/genome/） において紹介しております。
すべて 2015 2014
すべて 雑誌論文 (8件) (うち査読あり 8件、 オープンアクセス 8件、 謝辞記載あり 8件) 学会発表 (7件) (うち招待講演 7件) 図書 (1件)
Cell Cycle
巻: 14 ページ: 74-85
10.4161/15384101.
Genes to Cells
巻: 20 ページ: 242-254
10.1111/gtc.12216.
Mol. Cell
巻: 55 ページ: 123-137
10.1016/j.molcel.2014.04.031.
巻: 13 ページ: 1859-1866
10.4161/cc.29251.
Methods in Molecular Biology
巻: 1170 ページ: 279-293
10.1007/978-1-4939-0888-2_13.
巻: 13 ページ: 882-883
10.4161/cc.28216.
Seminars in Cell & Developmental Biology,
巻: 30 ページ: 110-120
10.1016/j.semcdb.2014.04.014.
PLoS Genetics
巻: 10 ページ: 1-17
10.1371/journal.pgen.1004667.
