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Investigating the Metabolism of a Major Peroxidation DNA adduct, M 1 dG, in the Genome
Author(s) -
Wauchope Orrette R,
Beavers William N,
Galligan James J,
Mitchener Michelle M,
Kingsley Philip J,
Marnett Lawrence J
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.573.2
Subject(s) - nucleotide , chemistry , adduct , dna , lipid peroxidation , dna damage , biochemistry , dna adduct , microbiology and biotechnology , deoxyguanosine , adenine nucleotide , malondialdehyde , biology , oxidative stress , gene , organic chemistry
Chronic inflammation results in increased production of reactive oxygen species (ROS), which can oxidize cellular molecules including lipids and DNA. Our laboratory has shown that 3‐(2‐deoxy‐b‐D‐erythro‐pentofuranosyl)pyrimido[1,2‐a]purin‐10(3H)‐one (M 1 dG) is the most abundant DNA adduct formed from the lipid peroxidation product, malondialdehyde, or the DNA peroxidation product, base propenal. M 1 dG is mutagenic in bacterial and mammalian cells and is repaired via the nucleotide excision repair system. Here, we report that M 1 dG levels in intact nuclear DNA were increased from basal levels of 1 adduct per 10 8 nucleotides to 2 adducts per 10 6 nucleotides following adenine propenal treatment of RKO, HEK293 or HepG2 cells. We also found that M 1 dG in genomic DNA was oxidized in a time‐dependent fashion to a single product, 6‐oxo‐M 1 dG, (to ~ 5 adducts per 10 7 nucleotides) and that this oxidation correlated with a decline in M 1 dG levels. Investigations in RAW264.7 macrophages indicate the presence of high basal levels of M 1 dG (1 adduct per 10 6 nucleotides) and the endogenous formation of 6‐oxo‐M 1 dG. Interestingly, in all cell lines investigated, 6‐oxo‐M 1 dG was not observed in mitochondrial DNA. Basal levels of M 1 dG in the mitochondria were found to be approximately two orders of magnitude higher (~ 1 adduct per 10 6 nucleotides) than those observed in nuclear DNA and were increased with electrophilic stimulation. Further studies, in all the investigated cell lines, indicated a correlation between M 1 dG levels and oxidative stress in the mitochondrion. This is the first report of M 1 dG in mitochondrial DNA in intact cells and it has significant implications for understanding the role of inflammation in DNA damage, mutagenesis and repair. Support or Funding Information This work was supported by a research grant from the National Institutes of Health, R37 CA0878819 (L.J.M.)