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  • 标题:Large-scale heterochromatin remodeling linked to overreplication-associated DNA damage
  • 本地全文:下载
  • 作者:Wei Feng ; Christopher J. Hale ; Ryan S. Over
  • 期刊名称:Proceedings of the National Academy of Sciences
  • 印刷版ISSN:0027-8424
  • 电子版ISSN:1091-6490
  • 出版年度:2017
  • 卷号:114
  • 期号:2
  • 页码:406-411
  • DOI:10.1073/pnas.1619774114
  • 语种:English
  • 出版社:The National Academy of Sciences of the United States of America
  • 摘要:Previously, we have shown that loss of the histone 3 lysine 27 (H3K27) monomethyltransferases ARABIDOPSIS TRITHORAX-RELATED 5 (ATXR5) and ATXR6 (ATXR6) results in the overreplication of heterochromatin. Here we show that the overreplication results in DNA damage and extensive chromocenter remodeling into unique structures we have named “overreplication-associated centers” (RACs). RACs have a highly ordered structure with an outer layer of condensed heterochromatin, an inner layer enriched in the histone variant H2AX, and a low-density core containing foci of phosphorylated H2AX (a marker of double-strand breaks) and the DNA-repair enzyme RAD51. atxr5,6 mutants are strongly affected by mutations in DNA repair, such as ATM and ATR. Because of its dense packaging and repetitive DNA sequence, heterochromatin is a challenging environment in which to repair DNA damage. Previous work in animals has shown that heterochromatic breaks are translocated out of the heterochromatic domain for repair. Our results show that atxr5,6 mutants use a variation on this strategy for repairing heterochromatic DNA damage. Rather than being moved to adjacent euchromatic regions, as in animals, heterochromatin undergoes large-scale remodeling to create a compartment with low chromatin density.
  • 关键词:ATXR5 ; ATXR6 ; H3K27me1 ; DNA repair ; DNA replication
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