DNA polymerase ζ limits chromosomal damage and promotes cell survival following aflatoxin exposure

Ying Chih Lin, Nichole Owen, Irina G. Minko, Sabine S. Lange, Liang Li, Michael P. Stone, Richard D. Wood, Amanda K. McCullough, R. Stephen Lloyd

Research output: Research - peer-reviewArticle

Abstract

Routine dietary consumption of foods that contain aflatoxins is the second leading cause of environmental carcinogenesis worldwide. Aflatoxin-driven mutagenesis is initiated through metabolic activation of aflatoxin B1 (AFB1) to its epoxide form that reacts with N7 guanine in DNA. The resulting AFB1-N7-dG adduct undergoes either spontaneous depurination or imidazole-ring opening yielding formamidopyrimidine AFB1 (AFB1-Fapy-dG). Because this latter adduct is known to persist in human tissues and contributes to the high frequency G-to-T mutation signature associated with many hepatocellular carcinomas, we sought to establish the identity of the polymerase(s) involved in processing this lesion. Although our previous biochemical analyses demonstrated the ability of polymerase ζ (pol ζ) to incorporate an A opposite AFB1-Fapy-dG and extend from this mismatch, biological evidence supporting a unique role for this polymerase in cellular tolerance following aflatoxin exposure has not been established. Following challenge with AFB1, survival of mouse cells deficient in pol ζ (Rev3L-/-) was significantly reduced relative to Rev3L+/- cells or Rev3L-/- cells complemented through expression of the wild-type human REV3L. Furthermore, cell-cycle progression of Rev3L-/- mouse embryo fibroblasts was arrested in late S/G2 following AFB1 exposure. These Rev3L-/- cells showed an increase in replication-dependent formation of γ-H2AX foci, micronuclei, and chromosomal aberrations (chromatid breaks and radials) relative to Rev3L+/- cells. These data suggest that pol ζ is essential for processing AFB1-induced DNA adducts and that, in its absence, cells do not have an efficient backup polymerase or a repair/tolerance mechanism facilitating survival.

LanguageEnglish (US)
Pages13774-13779
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume113
Issue number48
DOIs
StatePublished - Nov 29 2016

Fingerprint

Aflatoxins
Cell Survival
DNA polymerase zeta
N6-(2-deoxy-erythro-pentofuranosyl)-2,6-diamino-4-hydroxy-5-formamidopyrimidine
Aflatoxin B1
Chromatids
DNA Adducts
Epoxy Compounds
Guanine
Mutagenesis
Chromosome Aberrations
Hepatocellular Carcinoma
Cell Cycle
Carcinogenesis
Embryonic Structures
Fibroblasts
Food
Mutation
Survival
DNA

Keywords

  • Aflatoxin
  • Environmental toxins
  • Hepatocellular carcinogenesis
  • Mutagenesis
  • Translesion DNA synthesis

ASJC Scopus subject areas

  • General

Cite this

DNA polymerase ζ limits chromosomal damage and promotes cell survival following aflatoxin exposure. / Lin, Ying Chih; Owen, Nichole; Minko, Irina G.; Lange, Sabine S.; Li, Liang; Stone, Michael P.; Wood, Richard D.; McCullough, Amanda K.; Lloyd, R. Stephen.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 113, No. 48, 29.11.2016, p. 13774-13779.

Research output: Research - peer-reviewArticle

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AU - Owen,Nichole

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AU - Li,Liang

AU - Stone,Michael P.

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