UBC13-Mediated Ubiquitin Signaling Promotes Removal of Blocking Adducts from DNA Double-Strand Breaks

Chemical modifications and adducts at DNA double-strand break (DSB) ends must be cleaned before re-joining by non-homologous end-joining (NHEJ). MRE11 nuclease is essential for efficient removal of Topoisomerase II (TOP2)-DNA adducts from TOP2 poison-induced DSBs. However, mechanisms in MRE11 recruitment to DSB sites in G1 phase remain poorly understood. Here, we report that TOP2-DNA adducts are expeditiously removed through UBC13-mediated polyubiquitination, which promotes DSB resection in G2 phase. We found that this ubiquitin signaling is required for efficient recruitment of MRE11 onto DSB sites in G1 by facilitating localization of RAP80 and BRCA1 to DSB sites and complex formation between BRCA1 and MRE11 at DSB sites. UBC13 and MRE11 are dispensable for restriction-enzyme-induced "clean" DSBs repair but responsible for over 50% and 70% of NHEJ-dependent repair of γ-ray-induced "dirty" DSBs, respectively. In conclusion, ubiquitin signaling promotes nucleolytic removal of DSB blocking adducts by MRE11 before NHEJ

Clinical Evaluation of Newly Developed Two-Stage Hydroxyapatite-coated Dental Implant in Humans

本論文の要旨は平成4年8月2日日本口腔インプラント学会中国四国支部総会において発表した。本論文は,広島大学歯学部附属病院において行われた京セラ株式会社からの受託臨床研究における治験症例の観察結果をまとめたものである

Bony Interface of the One-Stage Zirconia Implant after 3 Months of Clinically Unloaded Condition

本論文の要旨は平成3年8月の第11回日本口腔インプラント学会中国・四国支部総会において発表した