Cellular repair of DNA–DNA cross-links induced by 1,2,3,4-Diepoxybutane

Lisa N. Chesner, Amanda Degner, Dewakar Sangaraju, Shira Yomtoubian, Susith Wickramaratne, Bhaskar Malayappan, Natalia Tretyakova, Colin Campbell

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Abstract

Xenobiotic-induced interstrand DNA–DNA cross-links (ICL) interfere with transcription and replication and can be converted to toxic DNA double strand breaks. In this work, we investigated cellular responses to 1,4-bis-(guan-7-yl)-2,3-butanediol (bis-N7G-BD) cross-links induced by 1,2,3,4-diepoxybutane (DEB). High pressure liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI+-MS/MS) assays were used to quantify the formation and repair of bis-N7G-BD cross-links in wild-type Chinese hamster lung fibroblasts (V79) and the corresponding isogenic clones V-H1 and V-H4, deficient in the XPD and FANCA genes, respectively. Both V-H1 and V-H4 cells exhibited enhanced sensitivity to DEB-induced cell death and elevated bis-N7G-BD cross-links. However, relatively modest increases of bis-N7G-BD adduct levels in V-H4 clones did not correlate with their hypersensitivity to DEB. Further, bis-N7G-BD levels were not elevated in DEB-treated human clones with defects in the XPA or FANCD2 genes. Comet assays and γ-H2AX focus analyses conducted with hamster cells revealed that ICL removal was associated with chromosomal double strand break formation, and that these breaks persisted in V-H4 cells as compared to control cells. Our findings suggest that ICL repair in cells with defects in the Fanconi anemia repair pathway is associated with aberrant re-joining of repair-induced double strand breaks, potentially resulting in lethal chromosome rearrangements.

Original languageEnglish (US)
Article number1086
JournalInternational journal of molecular sciences
Volume18
Issue number5
DOIs
StatePublished - May 18 2017

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Keywords

  • 1,2,3,4-diepoxybutane
  • Chinese hamster lung fibroblast
  • DNA double strand break
  • DNA repair
  • Fanconi anemia
  • Homologous recombination
  • Interstrand DNA-DNA crosslink
  • Nucleotide excision repair

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