Clustered DNA double-strand break formation and the repair pathway following heavy-ion irradiation

Yoshihiko Hagiwara, Takahiro Oike, Atsuko Niimi, Motohiro Yamauchi, Hiro Sato, Siripan Limsirichaikul, Kathryn D. Held, Takashi Nakano, Atsushi Shibata

Research output: Contribution to journalArticlepeer-review

59 Citations (Scopus)


Photons, such as X- or γ-rays, induce DNA damage (distributed throughout the nucleus) as a result of lowdensity energy deposition. In contrast, particle irradiation with high linear energy transfer (LET) deposits highdensity energy along the particle track. High-LET heavy-ion irradiation generates a greater number and more complex critical chromosomal aberrations, such as dicentrics and translocations, compared with X-ray or γ irradiation. In addition, the formation of >1000 bp deletions, which is rarely observed after X-ray irradiation, has been identified following high-LET heavy-ion irradiation. Previously, these chromosomal aberrations have been thought to be the result of misrepair of complex DNA lesions, defined as DNA damage through DNA doublestrand breaks (DSBs) and single-strand breaks as well as base damage within 1-2 helical turns (<3-4 nm). However, because the scale of complex DNA lesions is less than a few nanometers, the large-scale chromosomal aberrations at a micrometer level cannot be simply explained by complex DNA lesions. Recently, we have demonstrated the existence of clustered DSBs along the particle track through the use of super-resolution microscopy. Furthermore, we have visualized high-level and frequent formation of DSBs at the chromosomal boundary following high-LET heavy-ion irradiation. In this review, we summarize the latest findings regarding the hallmarks of DNA damage structure and the repair pathway following heavy-ion irradiation. Furthermore, we discuss the mechanism through which high-LET heavy-ion irradiation may induce dicentrics, translocations and large deletions.

Original languageEnglish
Pages (from-to)69-79
Number of pages11
JournalJournal of radiation research
Issue number1
Publication statusPublished - 2019 Jan 1
Externally publishedYes


  • cancer treatment
  • DNA double-strand breaks
  • DSB repair pathway
  • heavy-ion irradiation
  • radiotherapy
  • super-resolution microscopy

ASJC Scopus subject areas

  • Radiation
  • Radiology Nuclear Medicine and imaging
  • Health, Toxicology and Mutagenesis


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