title: Chromatin compaction protects genomic DNA from radiation damage.
abstract: Genomic DNA is organized three-dimensionally in the nucleus, and is thought to form compact chromatin domains. Although chromatin compaction is known to be essential for mitosis, whether it confers other advantages, particularly in interphase cells, remains unknown. Here, we report that chromatin compaction protects genomic DNA from radiation damage. Using a newly developed solid-phase system, we found that the frequency of double-strand breaks (DSBs) in compact chromatin after ionizing irradiation was 5-50-fold lower than in decondensed chromatin. Since radical scavengers inhibited DSB induction in decondensed chromatin, condensed chromatin had a lower level of reactive radical generation after ionizing irradiation. We also found that chromatin compaction protects DNA from attack by chemical agents. Our findings suggest that genomic DNA compaction plays an important role in maintaining genomic integrity.
authors.affiliation: Structural Biology Center, National Institute of Genetics, Mishima, Shizuoka, Japan ; Frontier Research Base for Global Young Researchers, Graduate School of Engineering Osaka University, Suita, Osaka, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takata
authors.forename: Tomo
authors.initials: T
authors.lastname: Hanafusa
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Mori
authors.forename: Mari
authors.initials: M
authors.lastname: Shimura
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Iida
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ishikawa
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yoshikawa
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yoshikawa
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Maeshima
mesh_terms: D002843:Chromatin / Q000187:drug effects* / Q000528:radiation effects*; D002945:Cisplatin / Q000494:pharmacology; D004247:DNA / Q000187:drug effects / Q000528:radiation effects*; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects*; D006367:HeLa Cells; D006801:Humans; D020287:In Situ Nick-End Labeling; D011839:Radiation, Ionizing
chemical_list: D002843:Chromatin; D004247:DNA; D002945:Cisplatin